Just in case you need to know how the Precision tubo's works, the guy in this video is running a Honda B16 (1600cc) making approx 600bhp on a Precision 6262, doesn't lag and he was running 1.5 bar (21psi) in this video
http://www.youtube.com/watch?v=UCylUskRCl4
Turbo sizing to volumetric efficiency, don’t get to hung up on turbo’s just for Rovers or VAG’s there are other options a good prices.