19" RUF wheels are very heavy compared to a stock OEM rims. Make sure the wheel's part numbers match up to a real RUF wheels. Lots of fakes out there. If these wheels did not cost you over $4,000 they are also fakes for sure.
Try calling RAC Perf. in Texas, they may know the wheel weights. They are the former RUF specialists in the USA:
Porsche, Ferrari, Lamborghini - Parts, Service, Upgrades & Used Car Sales - RAC Performance, Dallas, Texas