With a PTE 6768, can you think of any down side to a 4" (compared to 3") down pipe?

 

yeah more wheel spin from faster spool/more pOwA!

i couldn't fit 4" on my setup, if i could, i would be running one right now!

 

other than making it and being able to fit it there will be no downside

 

what manifold are you running? with a top mount such as a pfab log/elt, love fab, or any top mount leaving the turbo right beside the motor, it isnt really possible to fit a 4in back there. You would be able to do so with a bottom mount like an IP mani, the only problem is I believe your turbo is too large to fit beside the frame of the car. That leaves you with the only option of a front mount where it would be very simple to fit. O wait what is this? Casey^ has a CFT manifold for sale?

 

There is no downside, unless you consider faster spool-up and more wheel RPM a downside.

J. R.