GT1
Ferrari 550: 2% less torque, 5kg ballast
Ferrari 575: 5kg weight reduction
Murcielago: 4% more efficient, 15kg ballast
Saleen S7-R: 10kg ballast, 5% more efficient
Lister Storm: 95l fuel tank, Michelin tyres instead of Dunlop
Viper GTS-R: 20kg weight reduction
Maserati MC12: 2% more torque
Marcos LM600: 40kg weight reduction, alternative Michelin tyres, 3% more efficient, better rear brake cooling, 110l fuel tank
Ford GT40: 15kg ballast, 3% less torque
Corvette C6-R: 15kg weight reduction
Aston DBR9: 3% more torque, 7% more efficient
Corvette C5-R: no changes
GT2
BMW M3 GTR: 5kg weight reduction
Seat Toledo GT: 10kg weight reduction
Porsche 996 GT2: 15kg weight reduction
Porsche 996 RSR: 15kg ballast
Porsche 997 RSR: 20kg ballast, 1% less torque
Ferrari 360 GTC: 10kg weight reduction, 3% more torque
Ferrari F430: GT1 mid-engined tyres, 3% less torque, 25kg ballast
Panoz GTLM: Michelin tyres, 2% less torque, 20% more efficient
Gallardo: 15kg ballast, slightly better rear brake cooling, less engine braking, 2% less torque
Looks like the Marcos is going in your favour TT and Jeff
I'm going for the Viper GT1.... never driven it before
don't fancy sharing your setup when you were running it Jeff?