A racing game is the most fun when you are playing against a human opponent. Twin units or linkable drivers are the way to go.
If I was looking for one now, I would pursue Rush 2049. Starting to see them in the $500 price range. These are linkable so you could put together a nice row of them and have some competition.
If money was no object I would probably go for a Maro Kart set up, but it is still very pricey to own.
Classics worth considering if you don't want modern games:
Bronze age - Vectorbeam Speed Freak (vector game)
Golden age - Turbo
Not a big fan of Pole Position.