Re: Mustang Washing
If you have a driveway and a hose that you can connect hot water too, that's all you need. Of course, the driveway will be an ice rink afterward unless you wait for a mild day.
I suggest going to a coin-wash where you can do it yourself. Brush drive-thru washes are OK and won't harm paint as badly as people think they would. I ran two over a seven year period and never had one complaint except from an old Mercedes Owner who lost some more exterior trim and asked if I had found anything (lol). Turned out he didn't lose it in my wash bay, but just make sure there are no loose items on the car and it'll be fine. A lot of car washes have a brush option, you have to tell the attendant that you want the brushes and he/she will activate them just for your wash; they're not necessarily used for every vehicle.
If the salt is bad enough, your best bet is to get the Stang undercoated every fall. A lot of places say twice a year is proper (once in spring one in fall), but even with 6-7 months of winter here, one undercoat will actually last two years with 20K of driving per year.
A brushless wash won't necessarily clean the paint, you'll be paying $8 or so for a wash that will leave a film over your paint. Only paint contacted items (such as brushes) will remove that film. A good car wash owner cleans the brushes before the start of each day, and sometimes throughout the day depending on brush use. If you walk up and notice a lot of black/green on a blue velvet based brush as you mentioned, I'd stay away. A little bit of discolouration is OK, but excessive black colour and other marks would turn me off right away. Hardened oil residue can cause damage to clearcoats.
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!