The original post and Title of this thread say "Luxury Sports Car". A sportscar implies 2-doors. How could any viper owner consider something like a Benze / Lincoln / AcuraTL a sportscar. These are Boring 4-door Family Cars. Period.
There is Nothing Lux about a challenger.
Caddy XLR &&& Jag XK8/XKR are the two best options i see in this thread.
-The XLR is overpriced IMO
-XK8 is the best bang for the buck @ around 15-20grand
Find a great deal on a used XK8 and you can flip it in a year or two for the same price or minimal loss to fund your Gen4 ....OR Gen5 Viper