Reinforcement kit for Z3's whose subframes are starting to "pop" their spot welds.
Over time the OEM Differential mount will start to crack and lead to movement of the differential. This movement will start to cause the subframe spot welds to weaken and fail.
This kit is derived from our 318ti reinforcement kit for M Swapped cars. We have redesigned the kit once we had a Z3 come in the shop for a kit installation. BMW changed some of the design that our 318ti kit was designed around. We'll be updating pictures with the Z3 info in August, 2026
It does not include any reinforcements for the Z differential. You will have to purchase BMW part 41118398664 (Currently out of stock/backordered) . You section that part and install it OVER the factory differential (after cleaning it to bare metal and fixing any of the cracks in it). See images for more details.
We are currently developing an additional part to replace the BMW diff mount that is on international backorder. We hope to have it in production in September, 2026.
The kit is made from .125 steel and installs into the subframe. There is no removal of the OEM Differential mount. The lower OEM sheet metal is maintained.
This is not a kit for the weekend install. Lots of fabrication required. The entire rear suspension, differential and back half of the exhaust is removed. Very good time to replace/upgrade bushings (NOT INCLUDED).
The installation is pretty straightforward, but if you're not comfortable stripping the back half of the car, cutting into sheet metal and welding without ANY instructions, you should not tackle this on your own.
This is a DIY kit. NO INSTRUCTIONS INCLUDED. If you need a step by step, there are other kits out there that are well documented.
This kit *MAY* fit the E30 chassis. We've not tested it... It SHOULD fit, but it may take some work to use... or it may not ... again, we haven't tested it on the E30 chassis.
Kit installation is available at our St. Louis, Missouri shop for right around $3,000 with the interior panels behind the seats all already removed and reinstalled yourself. Budget an additional $1,200 labor if the panels are intact at drop-off. Izzy's will not be responsible for broken 20+ year old plastic trim mounts.
Please inquire for schedule availability.
