I talked to ST suspension and was told sway bars made for stock 240Z's with L24 drivetrain might not be compatible with my car. Is this true? If so what would be compatible with my car? 

If you have a 240Z then sway bars for a 240Z will fit just fine, a little extra displacement in the engine will have no effect.

4 hours ago, Silver-240Z said:

I talked to ST suspension and was told sway bars made for stock 240Z's with L24 drivetrain might not be compatible with my car. Is this true? If so what would be compatible with my car? 

What about your car makes you think it would be a problem?

several are for sale on ebay..  i know that the usa had thinner bars then the euro version.. euro had few mm thicker bars.. Like the shocks they were a lot stiffer!