I looked a the 61FX liner replacement cost, $99.99.
http://www3.towerhobbies.com/cgi-bin...?&I=LXCJ61&P=Z
OS parts prices make it unreasonable to ever considering a rebuild. Although the Super Tigre G61 ABC wasn't mentioned, the whole engine is just $20 more and they run great, true ABC engines also.
Buying an OS engine at today's prices with so many quality alternatives available in the market, I can't see taking the plunge. Go with the Evo. It's already in hand.