ok so i've read that 02 wrx rear rotors wont work with the 2pot caliper. while shopping for 06-07 rear rotors i noticed it said will work on wrx 02-07 so let me get this straight 02 rotors wont work with 2 pot but 06-07 rotors will work with 02-05 stock calipers??
06-07 rear rotors are larger than other year WRX's. You may be able to use other rotors, but you won't get the right effective braking because of the mismatch. 06-07 WRX rotors are 11.3" whereas other year WRX's with floating calipers are 10.3".
If you mount up the 2 POT calipers, you're going to miss out on a full inch of pad with your stock 02 sized rotors, which can cause a lot of issues on it's own. I would call up any place you're getting info from and make sure that they have the proper sized rotors for your application. I had to bring this up to a couple of vendors when shopping for new rotors, and they had to order new parts for me because the didn't know and didn't have it in stock. Don't move on this, and don't let them tell you that it'll work, because it won't.
Go there contact ken the owner, he has all right right kits/parts to do the swap, has great prices, and knows his stuff. Ken also posts on NASIOC all the time and and I have spoken and purchased from him a fews times always with great results.
Lastly, the Rear H6 upgrade is another choice. The 2pots cost quite a bit more money and H6 upgrade is really more bang for the buck. However, good pads (i.e. Stoptech Street Performance Pads), SS lines, Master Cylinder Brace, good synthetic fluid, and good tires can go a LONG way to improve your braking performance. I
I am running 332whp/338wtrq and still have the stock setupn on my '05, but the all the extra stuff I mentioned and I love my brakes. They have saved me from HORRIBLE Miami drivers many times.