What else should I consider?

Such as? Civic?

KIA STINGER is much faster and better on track and more luxurious

Audi RS3 if you live somewhere with bad weather.

Have you ever considered kit cars (Ariel, cobra clones, caterhams, Morgan [if that counts], etc)?

A new mustang gt

m2 btfo'd the mustang gt350 on track, mustang gt has no chance.

That front bumper though...

yeah it's really fucking bad
the m235i looks much better