I have a 489 case myself and have heard about putting a solid crush sleave eliminator in the case...where can i get it and how hard is it to put in? I will be swapping out the 3.23's that are currently on my center chunk for 3.91's, so will it be easily accesible to put in the sleeve eliminator at the time of the gear change? also, with this mod/upgrade is there different adjustability when setting up pinion depth or anything else i need to consider?