250-500cc cr250 enduro

might be looking into purchasing a 2004 cr250 and making it into a enduro bike but i do not need road registered, i can do the suspension and rewind the ignition easy enough, just need to know what other engine mods you might recommend, fww, reduce squish, port work etc.
i want a bike with a decent bottom/mid and mild top.
i will put on bash plate,guards etc.
i will keep the tmx as i got it working great in my 144.

You can get easy improvement in bottom end power w a flywheel weight for cheap Might need a thin spacer for the ignition cover- ez to make one yourself from aluminum.
A throttle cam system makes a big effect on power delivery- ez installation-again not much money.

If you put the WR ignition on it you would basically have a WR, and they really need nothing in the motor department for a great enduro bike.