The LDS one, also the duramax tuner ones use a stock compressor cover, the LDS one has a bigger higher flowing cover to keep the correct map groove in the housing. Lots of others modify the stock cover with a insert, weld, ect and the map groove is not as good.
Have you used either the lds or dt
2003 LB7
EFI LIVE
CAT FUEL FILTER
5 inch flo~pro
Sitting on 33*12.5-44 ballistic 959/Atturos