Top Gear Hot Hatches: I'd pick the Citroen. I'm a big fan of the Renault too but not as much the Clio as the Megane RS250 which is much more expensive.
Mustang vs Impala: I'd love to have a car that's called a "Super Cobra Jet." It'll be the Mustang for me.
Oh god, that's hard. I would have to drive them, really. I can't tell from what I've heard. I don't think I'd have the TT-RS, though. Not involving enough, though still cool.
Damn thats hard, all 4 look like they'd be fantastic cars... Ummm Evora. Cayman in a VERY close second. (Can I have both? Pretty please with a cherry on top)
BMW 1M vs. Audi TT-RS vs. Porsche Cayman R vs. Lotus Evora S - Ooh, that's a hard one... a very close tie between the Lotus and the BMW. I might just have to go with the BMW though, because I love that bodykit.