ive had my GTO for a couple of years now and have decided its time to up the boost. im going for an electronic boost controller but am unsure what boost pressure to increase it to. its a 1995 twin turbo, with a hks twin mushroom air filter and a aftermarket custom exhaust. runs half a bar at the mo. ive heard a bar is safe. is this true? also what spark plugs should i change to? im guessing i need colder grade plugs and was wondering what others have gone with. any help on this would be great. also does anyone know where i can get a bit of a guide to the fitment of a boost controller to a twin turbo? thanks very much for any help, steve :57:

Running half bar is below stock settings. You will have to figure it out but stock is 10 - 14 psi.

1.08-1.12 bar is normally wut we see GTO's use

there are a number EBC on the market and are the way to go to up the boost, I have a greddy profec B 11 fitted and I am boosting up to 15.5 PSI with zero knock! but I have supporting mods such as FMIC, walbro pump and hot wire, ek2 injector rail upgrade, fuel pressure regulator, a palm and data logging software (hand held halo) which is a must if you intend to fit any sort of boost controller its also advisable to make sure the engine is in good shape and change the fuel filter, most havent!
The greddy has Hi and Low boost settings a digital real time boost window, a last peak boost facility and limiter to safeguard over boosting, if you are in the UK use 99 octain petrol such tesco 99

hes definatlly right, as i do with all my cars Hih compression and turbo , i also use top octane petrol which is a best and must , especially when yu wanna boost up. Lots of guys never do and ask why they get knock retard and sum issues, and its because of petrol with low octane. It causes uneven and also pre-detination when boosting up