Can I keep my calipers and everything and just upgrade to bigger rotors from the fsvt, or even csvt?

try doing some searching and research it yourself. Both upgrades have been covered at length in a number of threads here.

The simple answer is NO.

The CSVT conversion requires adding CSVT or Cougar caliper brackets to move the caliper out enough to clear the larger rotor.

The FSTV conversion requires FSVT calipers (which includes caliper brackets) to lmove the caliper out enough to clear the larger rotor.

The CSVT will fit inside a stock 15" wheel. The FSVT will fit inside a stock CSVT 16" wheel.

This is covered in detail in the pinned notes at the top of this forum.