yes we cannot use the 4wd gearbox we must get a 2wheel g/b....For b8 the best g/b will be b6T(hard to find now days) 1.8 tx3 gb some even use lantis G/b and these gb cost around 2k or less depends on ur luck ....if the gearbox comes with lsd(very hard to find also) will be more than 2k
for b8 u dont really need oil cooler unless ur pushing over 300whp b8 got a build in oil cooler which runs with the radiator.......yes b8 180 hp halfcut also around 5k the b8 210 halfcut can go up to 9k
if ur going to use vr4 cooler will come around rm400-450 n piping will come around 1k ...
but if ur running 1 bar side cooler enough redi ....
ecu actully no need to change unless u want to high boost (1.5 bar ) go for haltech straight
but with good tuning n some upgrade like big fuel pump, vr4 injectors, safc, fuel regulator, wastegate, intercooler n boost controller n racing clutch u can boost it up to 1.2 bar ... like my car
with all this set up u can be looking around 200-210 whp
with this also good already to play with most 2 liters car