What gearbox to use with x18xe-1 turbo in Corsa c UTE

[Boetamac]

good day

I have a x18xe-1 fitted to my Corsa C-UTE. It has full stand alone management and 3weeks ago i fitted a GT2860. Its the biggest turbo i could fit in the bay.

I still have the 1.4 gearbox which makes the ute very nippy. But with the turbo it kinda runs out of revs so much quicker.

Which gearbox can i use in the setup of mine?

I can get a diesel gearbox, but im a bit apprehensive as it might keep the engine in boost at all the time.... killing the fuel consumption.

Any ideas would be appreciated

[LeratoGP]

I think F17WR box will help. Its from a gamma diesel.