Be wary of "inexpensive" wheels, especially if used on a road course and with higher-than-stock traction tires (220 treadwear, R-compounds, etc).
ASK for the wheel's "load rating" before purchasing - this will give you a starting point. And keep in mind that tires with more "grip" exert more force back into the wheel. Forgeline did a video recently explaining why their wheels have different load ratings based upon the tires you will be running.
And finally, remember: you get what you pay for.
Drive on...
Jeff Lacina
Owner / Lead Instructor
Track Guys Performance Driving Events
For the price, you can't beat APEX wheels for the stang. They do fit S550s now and I will be ordering a set, depending on this job I may be getting.
I've seen Apex's absorb a side impact and finish the race, only to find out they were cracked the whole way through and still held together with only a minor vibration.