Look for an aftermarket fork that says it's "suspension adjusted". It's a little longer from the dropout to the fork crown to adjust for the slightly taller static stance of a suspension fork.

It's about a "7" DIY project. Assuming you have a threadless headset you have to salvage the crown race off of your existing fork and reinstall it on the new fork. Your new fork also has to be cut to length. Measure carefully before cutting. Pretty much every bike mechanic who's not a liar will admit to having cut one too short.