What...no drawing of how this sentence looked on the TV from the couch? I was fully expecting to scroll down and find rabbit ears.

Sigh. Okay, here it goes, and remember it's been a while:

Only is an adverb, modifying the verb have. It is entirely appropriate for it to be placed before the verb. By modifying have with only, than yes, Bill, the sentence is saying that real performance cars can have only two seats, not three, not one. It is specifying the amount.

I think.

there is a difference between grammatical accuracy and literary import. A sentence can be correctly written different ways to carry different implications. As I read the tag line you mention, it tells me that real performance cars have two seats and nothing else.

Are they saying that caddies are basically soapbox racers for two, now? "The driver is basically ballast...."