I'm considering trading in my Koehler v-twin engine that came with my used Prochem Legend XL. What's the biggest baddest engine I could install (within reason, for best reliability)? My engine needs oil seals, wiring harness and some other parts. Compression did test great on both sides. Shop quoted me 1000 and change (CDN dollars) to fix. Debating just trading it. What would YOU do?