The 2871r always ended up with poor spool for the power. There were a few versions of it, but mainly the housings that were stock location were made to be universal to also fit 3071 / 3076, so they were too large for the GT28 to perform well in. People rotating were often looking bigger than that.
Look towards the GTX2865, EFR6258 and EFR6758 for small-ish turbos with broader powerbands. None of these solutions are cheap, but these are some of the first steps I've seen that seem significantly better than the old 16G Evo III --> 20G sized mitsu turbos.