[racer_d]

Whats the $$ for that vintage M3? I would have thought low 30s, no? For sure, you could find a pre 2002 911 or perhaps even a similar vintage 911 for mid 30s if you were willing to look a while.

Sell the GT3 as stand alone items. If in good shape, you could get 80% of what you paid for them. They wouldn't even know how to value them if you trade the car in with those seats.
How much more room do you genuinely need? Do you need to haul 4 people all the time? Is it luggage space? Personally I would rather keep a Porsche and a ****************box sedan/wagon/small suv for those few times a year I really needed the extra room (or just rent/borrow something if it is truly that infrequent).