GT28rs. I was considering this upgrade for my 530s (GT2554). The 2554s and 2560s share the same turbine wheel, but the 2860s use a slightly larger turbine wheel ( 53.85mm with a 76 trim vs 53mm with a 62 trim for the 2554s/2560s). I am concerned that the upgraded comp wheel and the smaller turbine wheel aren't a good fit (the comp wheel might move more air than the turbine wheel can get rid of). Don, any thoughts? :-]