I use my Mr Clean autodry system with Meguiar's Gold Class carwash soap+conditioner and have found it to work fairly well. The filtering system for rinsing also works well.
My proposition ?
Meguiar's make an aluminum alloy and heavy duty rubber soap dispensing hose nozzle with adjustable features :
An on and off switchable soaping feature ( that can be adjusted from a flood spray to a jet spray) , and the ability to have straight hose water run through to rinse ( with adjustments from flood to jet sprays).
I think a product like this from Meguiar's would more than sell itself as it vastly improves a person's car washing ability.\
This is what I do everytime for what I consider to be the best washing method ( to my current knowledge with with a Mr Clean Autodry)
1. Fill up the gun with some whatever soap you best prefer ( for me its GC carwash all the way)
2. Spray the car with soapy water first thing from top to bottom covering the car in soapy water from all angles. I like to spray soap into the wheelwells and on the tires and rims as the GC does a pretty decent job of breaking down grease and junk on tires and rims.
3. Let the car sit for a minute while the thick grime is dissolved and other stuff breaks down.
4. Rinse the car from top to bottom, and spray out the tires, rims, and wheelwells,
5. Repeat step 2.
6. Wash top to bottom , using appropriate wash mitts, brushes, and tools for each area of the car. For bug and tar removal : I use a cloth netted sponge for a bug/tar scrubbing device and takes out almost any bug or tar spot... if you soak it with some pure GC soap, blot the tar or bug ( so it has a layer of soap covering it) , let it sit for a minute, then scrub it off. This method takes out about 80% of tar and bugs . The rest need to be clayed off . I hear that the GC bug and tar remover works well but I am yet to use it.
7. Now rinse the car with regular water and make sure the tires and wheelwells are done too.
8. Run a MF towel or proper drying towel over the car as to get the majority of the water off so the spot free rinse will take less time.
9. Flip on the filtered water and slowly work from the top to bottom of the car. It took me a few times to figure out how to attain a truely spot free rinse, as the water in my area is hard and I at most get 3 washes out of one filter. It usually takes about 10 minutes to spot free rinse a car as you must get all the regular rinse water off the car starting from the top and work your way down.
I've spent more than a dozen car washes on my family's and friends vehicles over 2 months figuring the best washing method possible. I've had comments on how the car looks like it got waxed, even though it the real process of detailing the exterior had just begun.
Wow, that sure was a random tangent... although I would like to see Meguiar's produce the Nozzlator Soap spray nozzle in stores someday soon, although the "spot free rinse" is really just a bunch of hooey, as replacement filters run 5-6 bucks a pop and aren't cost effective, although for time saving they can be nice, but quality does not come with corners cut.