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      04-11-2011, 10:19 AM   #11
Second Lieutenant

Drives: '06 Z4 Coupe
Join Date: Oct 2007
Location: Houston

iTrader: (1)

Originally Posted by -c- View Post
well you cant mix and match unless the caliper is made for it, so if you have an 06 SI you need the 325 in the front if you pute a 300 in the front it wont work and youll be screwing things up as well as brake bias, the rear rotors are different for the front vs rear so you cant take fronts and switch them to rears.

you can upgrade to 330I rears and keep the fronts at 325MM then you will have a brake bias the same as the "I" technically speaking. as the only difference between the I and SI brake wise is the rotor was larger in the front and had a bigger caliper, the rear calipers are the same. Thats why its very easy to upgrade the I to SI brakes as they are simply bolt on.
thank god i found your post...after researching more, I got screwed. The rotors I have are 300mm but per realoem, they are for a z3, 323i, 325i,ci,xi and 328i,ci . So I'm screwed and have to buy new fronts as well now. But at least you saved me a huge headache. It sucks that all the websites that sell parts have the part I have now to fit my car's fronts. Incredible. Thanks again for your help!
edit...yea, can't return as I bought this off someone at a z4 forum.