First off, welcome to the site. Lots of good info on here, so get ready to spend some $$$
It is always good insurance to get the crank welded, but with a stock stroke, low compression motor, its up to you. I think a well set up motor like yours will be around 50-60hp depending on the porting.
For future upgrades, you might want to look into a few other parts. Pancake bearing clutch adjuster, billet impeller, timing plate, reeds. The list will go on and on. Most of what I just mentioned is good for a reliable motor