Hi Chris

Many more people on here know more than me but I will put my 50p in

I recently sold an escort and that was 415 bhp

It had group a head gasket
Siemens 72lb injectors
T34-63
Uprated in tank fuel pump
500 intercooler
Wasted spark
Two stage Boost controller 15psi 300 bhp or 30psi 415
14mm inlet spacer
Live mapped by James@ MSD.

The engine was standard, 400 bhp in my opinion is easy to achieve its when you go for the 450 bhp mark gets a bit more expensive.

I was told I could of achieved 440bhp by installing a AB07 inlet cam and swapped the turbo for a T38 turbo still on the above set up.

Step up from from that you would need head work (porting) pistons out skimmed for lower comp and valve cuts to allow for a higher lift cam ie bd14 ect. You can still use the T38 but would need to have a billet compresser wheel but is about £900-950ish exchange so not cheap and they still use the T34 turbo and bore it out but good for 480bhp ish.

Motorsport developments
Norris motorsport
Grove garage
Would be my choice if I was going that route.

or you can go another route, install aftermarket engine management big injectors, 7064 EFR turbo and manifold and achieve 450-470bhp and have a really responsive road car.

(Altho the aftermarket ecu is not necessary)

There's a car floating about on the forums that's done the efr route and the car RR at 470 bhp @ 490 lb on a standard engine with a group A head gasket.

This route I'd use MADevelopments

Hope this helps and don't throw up too many opinions

personally I wouldn't even bother with 350 bhp stage 3, green injectors. Two slow especially if you have 4x4 it loses to much power through the transmission. 400 bhp minimum for the win..

Cheers Si.