My original install was a Banks PowerPack on my 97 California truck. It included an IC, the 1.0 turbo housing, downpipe, mandrel bent 3.5" tailpipe, bad Banks Ottomind chip and POS Banks guages with the EGT stuck post turbo into the downpipe. This setup actually worked very well with the California truck although pricewise, it was a poor deal and the Banks chip would run prety high EGTs. Without a chip installed in it, the truck would make about 245 horsepower or so with very good spoolup for towing.
I used the 1.0 housing with stage II 160s. I think most of the detractors of the 1.0 housing either have never used it or did something really stupid like sledpulling or burning as much rubber as they could.
My truck also dyno'ed over 400hp again with the stock muffler (nothing else about the exhaust was stock). It did run better with a true 4" exhaust though. The truck also ran a 14.5 quarter with a 1.99 0-60' time, again with the stock muffler. This was with antique 2003 DieselPower tunes.
I tow a 10K trailer with this setup, the tow tune made 385hp.
I swapped the stock 1.15 housing back in and lost about 1/2 second on the 0-60mph time. Went back to the 1.0.
I once dyno'ed the usual 400 hp and on the way home, a 500hp single turbo cummins came out to play on the freeway. He had been at the dyno meet,too. So. he figures he's gonna get some cheap meat and rolls it on from 65. I let him get 2-3 lengths in front and then stuck it. By the time 95 came up, I was on his bumper. So much for the lack of top end with the 1.0.
Theres something to be learned here. One is don't be stupid, always spool the turbo before playing games. Two, I don't think the 1.0 lacks that much top end. Three, once you do this, your sleeper truck cover is blown for sure.

imp: