h23 and gsr trany are not that close in gearing look at the final drive. All h series tranys are high thats why everybody is going h2b plus the 20percent lose in moving parts which ads to hp on the dyno. As for the hp you are wanting and the money difference and it beind a dailey driver buy a m2b4 thats the lowest geared lsd trany there is for a h ( besides the tyoe s trany which you want find) or a m2a4 same gearing no lsd i promise you will be more then happy with it. About three months ago there was a m2b4 on here forsale for 400 so if you look you can find one reasonable. Later on down the road if you decide its not low enough buy a lower final drive still less then the h2b kit and the bseries trany.