gonna be many diff. views on this subject, CT9's are at their peak at 1bar, but don't expect it to last running that for long, yes they can be run at that but it's never good to run a turbo at it's limit day in day out. but then we can get into hybrid Ct9's which is a whole diff. subject, so in short in my opinion if you want to achive 210bhp with a std ct9b (with suporting engine mods) then you'd need a hybrid or a more tried and tested turbo like TD04, something to think about before you go buying a new manifold because you'd be wasting money if you decide to go for another turbo down the line. & yes, turbo's are better with upgraded mani's, 4E-FTE std manifolds are quite restrictive, so the more flow you get through the turbo, then quicker it spoils....etc