For a stock B18A1 block, don't rev over 7k, ever. That's how you cause oil starvation and spun rod bearings, not a very good thing if you expect the engine to last.

Don't buy cams until you decide if you want turbo or N/A. Both are very different in their grinds, and if you settle on an inbetween, you'll make max power in neither.

$400 is a kiss-ass price for a PR3 head. I remember when hmotorsonline.com was selling complete B16A longblocks for $450 less then a year ago. Then again, I did sell a mostly stripped P72 head on ebay a couple years ago for $550...

Anyway, decide how you want to go first, then the good advice will follow. For N/A, you can probably go faster for the same price without a VTEC PR3 or P72 head. For turbo, keep the head you have.