i have only vented rotors in the front. and i wanted to upgrade to the larger vented rotors in the rear from corksport.com

are the calipers any different in the rear? or can i just swap from a solid rear rotor to any FC vented rear rotor?

 

If you're talking about the Corksport rear big brake kit then don't. That's meant to balance out a front big brake kit, and since you don't have one, it will ruin the brake balance and give you terrible rear lockup problems.

Yes, you need different calipers. The vented rotors are wider, so you need a wider caliper and bracket, along with the vented rotors. Me, personally, I'd just go down to the local parts store, order some rebuilt calipers and new rotors and do it that way. No sense in paying for rusty old calipers of questionable remaining life.