LOL, if I could not take the heat, I would not be in the kitchen!
Not to throw out too many phrases on top of the kitchen one, but you cant judge a book by its cover.
If you were to make that visual comparison of the Powertechs vs the Solos, you would also have to include ST, Vogtland and H&R - all who use the Gold Zinc plating and are also much more expensive - none of which cover corrosion under their warranty terms.
The key on the Solo's, the ST, Vogtland and H&R kits is the thickness of the coating in comparison to the others. The thicker and golder the coating, the longer the metal can resist the salt - but no matter what there is always a breaking point.
In the end it is my experience that with coilovers it all comes down to maintenance, both preventative and during the winter season.
For many it is not practical to do anything but drive their vehicles in the winter - cleaning may not be an option at all. For those individuals, a stainless steel based coilover like KW is the way to go - or a winter only vehicle
Glen @ AMI