The center caps from the infamous 1985 GTV6 metric wheels will fit well and look very nice on the StilAutos. I have the same wheels on three of my GTV6s and have used the metric caps with success. You will need to apply some silicone as the fit isn't quite close enough for a press-fit. I've had no difficulty finding these caps as most GTV6 owners no longer use the Speedline metrics because of the ridiculous cost of new MIchelin TRX tires.