im thinking about buying a gti6 inlet manifold for my mi16 but the one im looking at( on ebay) doesnt have the fuel injector rail with it ...can the mi16 one be used or do i ned the gti6 one ??

iirc the fuel rails are different, so you'll need the GTi6 one. Someone will hopefully confirm/condemn this though!!

I'm assuming from your signature that you're talking about fitting it to your ph2 2.0.

If so, its easy enough, ive done the same thing. You use the original 405 fuel rail and injectors (the gti6 ones would work but would run terribly without a remap). IIRC all else was required was:
Remove the manifold locating dowels from the head then it bolts straight on
Sort out the idle valve pipework - I just connected the original idle valve to the housing for the 6 stepper.
Take a feed for the ecu map sensor, i used a t-piece in the vaccuum line that goes from the manifold to the fuel pressure reg.
Swap over sensors from the original tb to the 6 one - you need to use the original 405 TPS, and air temp sensor.

I think thats about it. Sure there will be something ive forgotten but youll work it out as youre going along!

decisions decisions ...im not sure what to do ...fix the original inlet system or fit the gti6 one ??
Will the torque of the engine be as good with a gti6 inlet bearing in mind its a bigger throttle body without tuning it further ?
will it not run weaker due to a higher flow of air due to the biiger tb??