honestly the stock block is supposed to be good for about 300HP. 10PSI (depending on the turbo) will get you to about 200-220 WHP. that said, if you have high miles on the engine i would just rebuild it. as long as you use pistons for the focus (forged of course) with the eagle rods for the focus you will have no problems there. look through these 2 threads and you can see what i did.
as for a turbo kit i am the only person that makes one. PM me if your interested. my kit costs ~$3500 and it includes everything except for a tune (you can get that either from a local tuner or through Warmonger).
any other questions feel free to post or PM me.