1.
Best B class car for IGC is the Pontiac Solstice (if it's still IGC), the M3 is a good car, but it lacks acceleration and top speed .
Solstice can stay in B class even ultra tuned while the M3 gets to A class with 2 or 3 ultras and 3 street parts , which makes the car weak vs the Solstice .
Even though it handles good , the M3 gets smoked by Solstices unless the track both drivers are racing is in Silverton , where the M3 may win because of its awesome handling .
^Makes me feel sad about selling my 595 OA Solstice .
Be careful with the Solstice tuning , try to use just one or none red(Attack) handling parts or it will oversteer badly in turns with or without nos .
If you are looking to do private races where nos is not involved you should choose the Mazda RX-8 (or '09) , it's the "no power ups" king in B class , weak nos makes this car not be in the top 3 B class kings , but if nos power would be equal on all cars RX-8 would own ANYTHING in B class. So do consider buying this car too .
2.
Some cars have bugged stats , some cars have their handling stat decrease no matter WHAT parts you install , a car has acceleration stat bugged (911 GT 997) , other cars' stats go up like crazy (especially the latest cars released like Ford Capri , A3 , Caterham and I think "the-thing-without-an-windshield too , I haven't got the chance to try It out yet .Other cars' stats just don't go up unless the part is really good like Charger R/T , Challenger R/T or Eclipse GT .These cars cannot even reach B class .
Anyway , even though the stats go down , that doesn't mean the actual performance of the car is going down too .