The Spec3 build is intended to be low cost and the parts used are intended to be easy to find. However, some of the parts used are much cheaper if you find them used or rebuilt. The full parts list is at the link below, but here are some items you should specifically consider as they are much cheaper with a little legwork.

Differential: The Spec3 differential is a 3.15 limited slip unit built to factory specifications. No fancy clutches or ramps allowed! These can be found used for around $400 and came equipped on most winter package 325i cars. Any differential/transmission shop should be able to rebuild one to factory spec and you can source then “new” from various sources like DiffsOnline. Most east coast builders will find a used unit and have it rebuilt by Danville Diffs https://danvillediffs.com/ and sometimes Danville Diffs even has Spec3 legal units in stock.

Exhaust: You can make your own Spec3 exhaust as long as it’s to the specifications listed in the rules, but you can also purchase a pre-built exhaust kit from Mitchum Enterprises.

Mitchum Enterprises Richmond, VA (804) 402 1239; richard.mitchum@gmail.com