You can get an LS2 Vette for mid/high 20s. Don't know what you're looking at with an STI but they aren't in the low/mid teens as far as I know. One thing I can attest, with a Vette you're likely to have had a previous mature owner. Buying the Evo/STI/SRT/Mustang/Camaro/etc. etc. etc. you're playing with fire in the used car market. One bolt-on (headers) on my LS3 and I'm ripping deep in the 11s at well over 120mph. Throw in a cam and I'm at 11 flat, throw on forced induction hello single digits and 140mph+ trap speeds. Different league of a car. This is just on the LS3 (not counting Z06 / ZR1).
Just saying. All are awesome rides but the Vette is a better platform to start off from.
I'm talking MSRP, the corvette is roughly 10k more