Alright, First off im the highest HP figure I want to ever hit is 650rwhp. So I'm debating on whether to go with the cast manifold of SS Tubular Manifold. I have heard the cast can spool the turbo up to 600RPM's faster, and this is very tempting because I really dont want any lag. I'm thinking of going with an SP57 or SP60 ( I know these cant produce 650rwhp.) So what do you guys think? If I'm looking to spool fast which do you think? And I'm not concerned with looks, more on performance. Thanks fellas!