Hi everyone, I'm looking into finally getting my uprev done at Horsham soon. So far on my 2005 gt I've changed the rear section of the exhaust, got a pop charger, Horsham d's silenced decats, ams light weight pulleys, ultra light weight flywheel & exedy clutch, and a d1 throttle controller. Do I need to change the x pipe to get maximum gains or is the stock one ok? Also I am adding a plenum spacer whilst having it mapped, should I see good gains? It's got 58000 miles and I've always used shell v Power since I've had it.