With N/A vr6 there are not really any cheap mods that give you much extra power. I have an early dizzy engine and found that re-newing the leads, plugs, dizzy cap & rotor made a big difference with driveability. When I did my conversion I also used a stainless 6 branch manifold and ported and matched the inlet side of things. With the vr6 it's the intake that restricts things so full exhaust system won't give you many extra horsies for the £'s you spend. A Shrick manifold helps but they are £££'s. I think a N/A vr6 can get to 210bhp ish max but that will cost as much as sticking a turbo on there which will easily get you 300bhp+.
You will be lucky to see a 4-5 BHP gain from a Schrick manifold even with 268 cams fitted...it's all about the huge midrange torque gains with that manifold.
The standard VR6 downpipes/manifolds are good for 225-230 BHP...so you don't need a 6 branch.
A well built 2.9 can easily see 220-230 BHP with the right mods...but, as said above, you can probably turbo it for the cost.
However, you don't get the throttle response and the huge torque of the VR6T just swamps the chassis and doesn't make for as nice a driving car, in my view.
