You should be able to do it, I am now 40hp over my stock motor figure of 168hp, with all my mods. I how have just over 170 hp at the wheels. I reckon if I had my mods carried out on a ST200 (or SVT as you guys have them) I reckon it would crack the 200hp@ the wheels barrier. On the issue of torque, I am currently pulling 191 lbs/ft, (at the crank) and its great! This is helped by running headers with no main cat, and porting and polishing.
If I did my homework, I would have gone with the 3L valves but its a bit late now...
