Not an expert but I just took a BW 0001 off my 15.8 5DS it was on for 30,000 and seamed to small the jakes were stronger and it was a dragster through the bottom gears but would surge badly on the top end and on long pulls you would have to back out of it to the point of almost coasting to keep boost below 40 or then the fan came on from high intake temps and that's with a new ata , pdi manifold and radiator ,I put the BW 175963 with 1,65 WG housing and it is a joy to drive a bit laggey 1450 and under but over 1500 it pulls strong , I bought it used and as far as I now is stock but it might have been tuned before I got it , It drags a bull rack around so I'm sure my likes are different than others and I know you guys work them harder but it is more to my liking now , I have friends with hot mbn and 6nz that love the 1.58 but it was unworkable for this motor