You let your car warm up before driving it? I just start her up and hammer down! LSXs may suffer from very slight piston slap and lifter tick but its nothing to have special warm up periods for. Not until you have forged FI pistons. Just dont rev it past 2500rpm before its warm as not to fatigue your valve springs.
Dont get into a stealth. They can be headaches. A friend had one and it leaked oil from everywhere and then found it had a cracked head… This also started out as a “great deal”
My Cutlass Ciera is the tits. 30+MPG mixed city and highway. The worst I got so far was 29MPG. Ask MK4 30R. LOL