A shop would be the way to go, get your parts from www.engnbldr.com and you'll be good to go. LC engineering and TCR sell performance engines, but they're a bit pricey.

On the cam subject, I had a Crane stage I (same grind as TRD stage I) in my old engine and it made a huge difference along with headers and a 2.25" exhaust. I had a nice tourqey powerband from 2.5-5k and if I stayed out of it I got pretty decent gas mileage.

'87 4-Runner--DD/wheeler, 4.3 swap coming soon
'89 Supra--E85 powered 2jz NA-T Swap, 533rwhp 497ft-lbs
'89 Festiva, turboed BP swap powered by megasquirt