I personally would look into getting an Atari 4-speed shifter to replace the 2-speed stock one.
With that addition, just about all the 360 degree driving games should be playable.
The Atari style ones (from Drag Race, Sprint, etc...) should drop in with minimal rework, and will not look out of place on a PP.
You can remap the inputs so that games that use a 2-speed are still playable with the 4-speed, but the 4-speed will give you a sizable increase in the number of games available, and make the cabinet more "complete".
The only games I can think of off-hand that use a clutch are all 270 degree games, which won't be playable anyway.