trident, if you are unsure whether it will outperform a HKS 2835 pro s (remembering that both the GT3071 & HKS 2835 pro s use a 71mm compressor) and then the only way to be sure would be to go the 76mm compressor.
if GCG are talking about the GT3071WG disco is going to try to talk you out of it as it has the cropped turbine, if it is new then it may be one of the new internally gated garrett housings.
ask about GT3076 that should give you a little more headroom or splash out on a HKS3037 (the HKS version of the 3076)
check atpturbo.com as they can supply a genuine GT30 internally gated turbine housing that you can mate to whatever combo takes your fancy.