What can I do to improve the reliability of a 2nd gen Rex? I know upgraded radiator would help.. I once read something about relocating the cat(??) by passenger leg side area... something about heating there.? and I know rebuilding would help but I need specifics.

 

Remove restrictive cat and replace w/ hi-flow or straight pipe; perform ATF trick, change plugs/wires/oil regularly, check engine oil every time you fill up on gas/mix in some 2-cycle oil with your gas (about 200:1 out to do it.)
Oh yeah, let it warm up before you get on the throttle hard. This is called preventive maintanence and it equal increased reliability.