Originally Posted by Sp3no

Having a lightened flywheel and stage 3 clutch fitted is the number 1 thing that transformed the car, yes it chatters at idle but acceleration in 1st and 2nd is greatly improved 0-60 sub 7 seconds, i have an uprated gearbox mount and CFM short shifter which helps also.
I wouldnt bother with a decat, they really make the exhaust note raspy and it will also make your ST170 very loud.
Exhaust vernier i would say is probably worth the expense if you do the work yourself. Apart from that i wouldnt waste your money.
Your could always port the standard TB for free which i have done to removed the big hump before the butterfly, wont give you extra power but if i so much as breath on the accelerator pedal the car takes off now.