Don't Go There...
If you want some good advice. (I should of looked into buying one like you have before I went and made an idiot of myself, which is where I excell tbh)
1. DO NOT get rid of your 172 for an EVO - BIG Mistake.
2. Don't listen to the majority of opinionated people on here.
3. Just don't bother unless you have got endless cash to burn eg servicing, petrol etc.
4. You won't see a massive increase in performance you expect if you go for a 260.
5. Don't say I told you so....
Take advice from someone who made the change from a 260 to a 172.
In the words of Ian Brown:-
"...keep what you've got...or else you'll be giving it all away".