I called a local detailing shop to see about having the exterior of my car washed/clayed/polished/waxed to get it ready for winter. This place has been in business since 1990 so I figure they know what they're doing. They told me it would be $120, or $170 if I opted for a Teflon sealant that was guaranteed for a year. Is this about what I should expect to pay for an exterior job like this from an experienced detailer?