Theres a few questions I have and was wondering if you guys could help me out.

When should I start looking for a new engine? When it blows or when compression is real low?


Or while it is running, should I just buy some new apex seals and springs to give it more life?

And when I do come to the fork in the road(no running engine), do you guys think my best bet would be to get a rebuild from RB for roughly $1k, a decent used engine, or go for the 12at from rotaryshack (which i drool over) ?
By the way, what major things need to be done to put the 12at from rotaryshack in a stock 84 gs?

I'm just worried about the rotary and want to keep it around. I don't want to move to pistons.
Thanks ahead of time guys. I appreciate it.