A local has the PIAA Pro 80 XT's in his stock fog location. Work great for him. I think for the price... the 500's are a better deal and although they are about a 3rd of the price, they aren't a 1/3rd of the light.
If you have budgeted $200 or so, then go with the 130 watt Cibie's or the 120 watt PIAA Pro 80 XT's.. myself, when the time comes... I can't justify that kind of cash for DL's since I won't use them everyday on the street (too bright) and they are quite nice for the money.
Jon