The same kit is used for both single and dual ear versions, and sells for $575.00 USD. I’ll ship anywhere in the lower 48 states for a flat $35.00. International freight charges are $135.00 USD. I can accept payment via Paypal ( from verified accounts only. A personal/business check or money order is also accepted. Checks will delay shipping until cleared. Paypal and money order payments are shipped immediately upon receipt.

The reinforcement package is primarily geared towards the ///M versions of the Z3, but with some options on choice, it is just as easily fitted to the Z3.

The biggest difference between the two applications is that on the Z3, the spare tire carrier takes up some of the space required to fit the dual ear differential cover from the E36 M3.  The choice is to either remove the spare tire carrier and its mounting bracket from the body (the tire can be carried inside the trunk) and use the dual ear cover, or to forego the dual ear in favor of keeping the spare in its original location.  If you do that, all the same trunkfloor pieces are utilized, but I recommend taking a second OE rearmost differential mounting bracket and sectioning it to fit over the original one.  By *sandwiching* these two brackets, you’ll double the thickness and strength of the single ear version.

My 99 M Rdstr has the doubled up single ear version with approximately 65,000 miles since conversion (95,000 now) with probably >20,000 of those miles running different superchargers (approx. 350 to 450 BHP).  My 01 M Rdstr has the dual ear reinforcement, with perhaps 20,000 miles since being upgraded. Currently the 01 has about 46,000 miles total.

If you have any questions about the reinforcement package or its installation, I will be happy to answer them for you.

Thanks again.

Randy Forbes

Sports Cars Plus, LLC

Parrish, Florida 34219




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Frequently asked questions for anyone considering the E-36 M3 differential cover with dual mounting points

By Randy Forbes/Sports Cars Plus, LLC

1. Speedometer function

The E-36 M3 “dual ear” cover will not fit over the large impulse wheel as fitted to the M Coupe/Rdstr differential, so the non-MZ3 impulse wheel and sensor must be installed. If fitted with, or installing, a 3.73:1 differential you probably already have the part required.

2. Exhaust system

The stock exhaust pipes will not clear the mounts on the dual eared cover without modification, or an aftermarket system can be fitted. I know the B&B, Eisenmann & SuperSprint will work. Dinans fit if the pipes haven’t been cut too short, but the Remus does not fit and AC Schnitzer may also have clearance problems. Your local muffler shop can always be relied upon to bend new pipes for the mufflers of your choice.

3. Structural enhancements

To allow the M3 cover to be fitted, the original mount must be cut away. The new pendant mounts are welded to the vertical membrane of an I-beam fabricated from 10 Ga. steel concealed inside the hollow OEM xmbr. The I-beam is suspended by reinforcements welded to the longitudinal rails of the unit construction chassis.

4. Appearance

Every effort has been made so that this modification looks as though it came from the factory that way. From matching the E-coat color, seam sealer and the textured coating applied before final painting, to making sure that all the trunk/hatch trim fits afterward. The only outward clue will be if looking directly at the differential cover where it attaches to the chassis.

5. Subframe bushes

I recommend the Ireland Engineering Subframe bushes to be installed with this modification. The reduced Subframe movement will be immediately noticed in the more stable and predictable handling of the vehicle.

6. Timeline

Budgetary estimate of thirty-two (32) hours is required. Due to finish curing times and fabrication work, please allow up to two (2) weeks for an individual car to be completed. Please schedule car in advance for minimal delays.

7. BMW parts required

  • Output shaft seal & clip 33 10 7 505 602 2) ea
  • Case side cover O-ring 33 11 1 214 144 2) ea
  • Cover gasket 33 11 1 211 708 1) ea
  • Fill/drain crush washer 07 11 9 963 355 2) ea
  • E-36 M3 (dual ear) cover 33 11 2 227 317 1) ea
  • Speedometer sensor 62 16 8 357 020 1) ea
  • Sensor O-ring 33 11 1 206 166 1) ea
  • Smaller o.d. impulse wheel (supplied by request)

8. Aftermarket parts required

  • 1-1/2 to 3 quarts Red Line 75w/90 or 80w/140 axle lube
  • Rogue E-36 M3 differential cover (optional)
  • Exhaust system of choice
  • Ireland Engineering subframe bushings (optional)

9. Refinishing supplies

  • DP 50LF/402LF-chromate primer
  • 3M seam sealer # 8505 (or equivalent)
  • Fusor # 805 wheel house textured coating (using # 312 application gun)
  • Topcoat(s) to match factory E-coat and body color (when required)
  • Solvents for cleaning & mixing, a/r

10. Trunkfloor Damage

  • Excessive trunkfloor and crossmember damage will be repaired based on time

required at currently published shop rate ($60.00/hr.)

11. Aftermarket Stereo/Sound Systems

  • Additional charge (at current rate) for disconnecting/reconnecting aftermarket

sound systems (amplifiers, speakers, crossovers, sub-woofers, etc.)

Now that you have a better idea of the process involved, we’ll move to the bottom line.

For $2500.00 I will supply and install the dual eared differential mounts and fit the differential cover of your choice to the original differential.  This includes refinishing materials and my consumables (listed in item # 9 above).

If you want Ireland Engineering subframe bushings installed, add $200.00 ($100.00 for parts/$100.00 for installation).

None of the items listed in #’s 7 & 8 are included in the above price.

If you have any questions and want to discuss this, please call between 10:00 AM – 7:00 PM Eastern Time and I will answer your questions. This extends to any potential installer who may be quoting the work for you, if my location is deemed too far.

For anyone considering shipping their car, please call Deb or Jessica McCauley of Descendants Trucking for a transportation quote: 419 490 4858. They have been my exclusive hauler since approximately 2010; I and all concerned parties have been satisfied with their service.

Please note that I am capable and willing to perform additional maintenance and upgrade work on your Z3 or ///M Coupe or Roadster, ranging from simple services to virtually anything you can imagine. Specialties are connecting rod bearing services for S-54 engine cars (2001-2002), VANOS overhaul services, transmission shift pin updates, suspension upgrades and forced induction (superchargers and turbochargers).

ALL work is documented with “in progress” photographs posted online with periodic uploads.

See completed and cars in progress here:

Thank you for reading.

Randy Forbes

Sports Cars Plus, LLC

Parrish, Florida 34219


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For more information, please contact me directly at:

You can order the reinforcement package directly by sending $575.00 plus $35.00 flat shipping fee (lower 48 only, Alaska, Hawaii and International via USPS with insurance & tracking is $135.00 USD) to my Sports Cars Plus, LLC Paypal account, and your kit will typically be shipped out the next business day:

Thank you for your interest, and please, check out all the repaired and reinforced cars in the gallery!

Randy Forbes