I found out something surprising when I talked to MRC recently...apparently my turbo is actually a GT3082R, but all this time we thought it was a GT3076R! For those who don't know, a GT3082R has the turbine from a GT3076R and the compressor from a GT3582R.
The reason this situation came about is because my turbo was very briefly used by a different workshop on a different engine before ending up on MRC's shelf for a while, then MRC sold it to me for a good price because it had been used (for a very very short time). MRC was told that it was a GT3076R, so the workshop which originally used the turbo is at fault for misinforming MRC.
This discovery might explain why the turbo has slightly more lag than I initially expected it to have, but still a bit less lag than a GT3582R.
The GT3086R may have a reputation for having a 'mismatched' turbine and compressor, but I've been happy with it (and of course I've been oblivious to the mismatch all along)! I've never experienced compressor surge or anything like that.
The only reason I'm even mentioning this is to avoid misinformation on the forums.