Hi,
I have intake, dp, hi-flow cat and cat-back. If I just keep the boost at stock level by Profec B , can I still use the stock ECU? I don't want to add boost before I can a aftermarket intercooler.

 

Yep, you should be fine if you keep boost to 10 psi. You definitely want to make sure you are not spiking at ALL.

To be safe, I would go to a dyno shop that has a wideband to make sure your A/F ratio is staying conservative (about 11.2:1 or so) at high rpms.

 

is that possible? the WG can not be controlled DOWN can it? a boost controler is there to UP you boost levels.
if you are currently seeing (lets just guess a number that is about right with your mods) 12lb now, i doubt you are going to be able to turn it down. but what do i know...
and why would he waste money on a dyno sesion? i personaly think this is bad advice at HIS stage of the game. if he does not have the (how much do they go for used now...?) $400 for a used pettit ecu, why spend money on dyno time now? save the money you would use there and put it into an upgraded ecu.

 

Usually, a hi-flo cat provides enough backpressure to not overrun the stock wastegate. He should be ok with controlling boost with a boost controller.