My problem is this:

When I step on the gas hard to get boost I get instant 12psi boost like you would
on the stock sequential turbos but if you back off for a tick and get back on it on the same gear it only gets up to 8psi, it will only go back to 12 psi if you shift down.It will do it in any gear step on it 12 psi back of slightly and back on the gas and only 8 psi.

If I go from first to top gear on boost hard run (like drag racing) evrythings great,no transition problem,boost steady till redline

Any ideas? Driving me nuts. Dont know if this is relevant but heres the mods:
HKS Intake,d/p,m/p,catback,Greddy smic,PFC,stock engine,stock injectors,stock seq.twin

 

You have a boost controller?

My car does the same thing, but I believe it's because of my boost controller settings. I'm about to reset and retune everything this week.

Your ECU can only do so much, it'd be good to look into a controller if you don't have one.

 

Using the PFC boost control. I can get the boost set up ok with playing around with the duty cycle but I cant get rid of the flatspot once you back off the throttle
and on again after boosting....Any other ideas?