The LS engine is actually from the Jaguar.
From what I found in the past the et for the V8 LS is pretty much the same as the SSEI. Considering that the LS is only a tenth of a litre larger and isn't supercharged I would say that'* pretty good.
I was close to buying one before I got the Bonneville. I decided it wasn't worth the added maintenence costs, but the '03 V8 I drove was pretty sweet. It had plenty of power and handled great. I thought the seats were comfortable as well, and the cooling feature would be nice for me since I'm always hot.
2003 Black SLE-Stock
2000 Mercury Mountaineer
1968 Oldsmobile Cutlass Convertible-455 cubic inches of muscle