Ok, they are back. We have such an odd spread of posters, though, it's hard to categorize them. There are 550+ users, but only 35 people have more than 50 posts, including admins. I think there is only one person who falls into the middle "4.0L IMSA V8" category.
Since you've all seen all the ranks by now, I will list them out:
New Member 3.5L V6 Member: 215hp 4.0L V8 Member: 250hp 3.5L IRL V8 Member: ~650hp, used in the IRL for 2001 on. 4.0L IMSA V8 Member: ~650hp, used in the IMSA WSC winning car in 1996, won outright in Sebring and Daytona that year, contested LeMans but retired 1/2 way with a gearbox failure. 4.0L IRL V8 Member: ~700hp used in the IRL for 1997-2000 seasons. 4.4L IMSA V8 Meber: ~750hp, used in the IMSA GTS-1 winning cars in 1996, dominated their class winning 10 of 11 races. 4.0L TT ALMS V8 Member: ~900hp, twin-turbo version of the IRL V8. Used in the Cadillac LMP900 for the 2000-2002 ALMS seasons as well as contesting LeMans. It podiumed a few times but never did as well as hoped, due mainly to the car, not the engines, shortcomings.