sure while your at it why don't you wax it with a brillo pad? Maybe clean the top with Clorox? LOL
DO NOT WASH YOUR PORSCHE IN AN AUTOMATIC CAR WASH.
You will get soap on the canvas top. don't ever get soap on the canvas. Just rinse it and use the
Raggtopp kit when its dirty.
if the car wash has a wheel track that's trouble for your wheel paint.
Wash the car yourself using two buckets. One with clean water and one with soapy water. Use a water softener like
Optimum No Rinse in both buckets. Any car wash soap will do. Take the spray nozzle of the hose to rinse. Dry with a
waffle weave towel. Maybe spray a quick detailer on while the car is still wet/damp before wiping dry. This reduces the swirling, you should avoid rubbing on dry paint.
If you don't have a hose fill a bucket with warm water and add a couple of ounces of Optimum no Rinse and after soaking the car, wipe the paint down paint in one direction, dunk the sponge and repeat. This method has become very common for high end pro detailers because it gets the car clean in the least amount of time...without having to use a hose.
If you absolutely must wash it away from home, find one of those coin operated car washes where you spray down the car yourself but don't use their brush and their soap. First stop by Pepboys, Wal-Mart and buy some car wash soap (I like the turtle wax clear soap) a sponge, a Meguiars Gold Class wheel face brush, two small buckets and buy a waffle weave towel from
Bed and Bath. Once you have all your "supplies" put in the quarters and add soap to the two buckets, fill with water all the way to the top, rinse down the car itself, Rinse out the wheel wells, rinse the top WELL, and rinse under the bumpers. Put down the hose, brush your wheels and tires with one bucket, and then wash the paint and glass with the other bucket. Take your time. Then fill the coin machine up again and when the water comes on just rinse everything down.