Erik, the 71HTA works PERFECTLY just as it comes with 8cm turbine housing and even with small compressor housing, it's amazing! It can't compete with the turbo you have, but at the price it's a VERY nice little turbo. It delivers what the 68HTA couldn't deliver, spools about the same as the former, but with LOTS more power.
But to be honest, a TD05H 20G with 8cm turbine housing is quite similar... I couldn't compare both in the same car and neither was I able to push the 71HTA to it's limits (because running out of injector), but even when ABSOLUTELY not pushed the 71HTA outperformed the 68HTA quite easily.
The turbo you have is not comparable with a GTX3071R as yours is noticable smaller, it has the "normal" GT3071R turbine wheel, combined with a 68 mm billet compressor which flows about the same as the Garrett 71 mm compressor. Because of the smaller and lighter compressor the response of your turbo is better than the non-billet version. It's an amazing turbo! (as you have discovered)
And the HTA71 isn't a super "boner" type of turbo (to take your words), but it does a lot of things very well.