I wouldn't spend a lot of time nor money on Ultra parts unless the wheels are only for show and around-town driving. These were built like pure racing wheels (3-piece bolt-together, with disassembly & X-ray/ visual inspection done by an experienced wheel man, after each event). There have been far too many catastrophic failures with these wheels on street cars to bet your life on them at high speeds. The latest was only last Fall; a GT5-S was driven 'vigorously' about 50 miles thru the mountains to a friend's house, and while everyone was standing around admiring the parked car, one 17" Ultra outer rim-half suddenly cracked horizontally half-way around the bead, instantly deflating a rear tire. If you own a set of these wheels, be VERY cautious: check the torque on the ring of bolts holding them together at least once a year, check tire pressures frequently- any sudden loss of air means a complete disassembly & X-ray inspection, and look for the beginnings of cracks every time the engine is started. They are very light, attractive... and dangerous! The wheel mfgr (not Hall) is out of business so replacement rim-halves are not available- one of the only pluses of this type of wheel. All that's left are a few accessory parts. I suggest using them on your Pantera or Mangusta exactly like a 38-year-old set of original Arriva tires!