Porsche, smaller so easier to hustle down country lanes, and cheaper running costs than the GTR.
Wouldn't say no to either, and both with a remap are stupidly quick. GTR gearboxes are weak though so you would have to factor in costs to upgrade that even when just mapped it seems. All my mates with GTR's have had to have gearbox work done (one even had 3 new gearboxes)