J's racing big brake kit
 

http://www.evasivemotorsports.com/merchant...uct_Code=B6P-S1
The kit has two 323mm rotors. But the j's racing rear brake rotor kit
(http://www.aj-racing.com/catalog/pro...&cat=81&page=2)
has 330mm rotors. Most big brake kits that I've seen, including the stoptech kit for the s2k, use 330 mm rotors [brembos too] (for the front i believe). Why did J's not go with 330mm in the front, and should there be concern about brake balance?