Yes a large exhaust will kill your primary turbo.
I have a Rage system, 2.5inch (siamese front pipe) front to back which has a much greater exhaust flow compared to the p shooter factory pipes.
The extra flow reduces back pressure allowing turbo to spool faster. Not a huge issue though, just means you need the wastegate to open more.
Take it to someone that knows subs and get it tuned. Pretty sure its just drilling out the brass pill in the vacuum/boost line to the wastegate actuator, this allows it to open more, not sure if anything else needs doing though.