I've got the same wagon and have been able to fix up the paint reasonably well with a Porter Cable 7424xp. I am just a hobbiest and am not at the level as the author, but have been pleased in what you can do with off the shelf product and the Dual Action polisher. I spent several hours just reading at Autogeek, Autopia, detailers Image, and Meguiars forums to start understanding the issues.
http://farm3.staticflickr.com/2834/9598038235_30f059c983_c.jpg
Subies are known for soft clearcoats. What that means is it is relatively easy to fix up the clear coat but also just as easy to scratch it up during washes in quick detailing.
On the polisher, I got an after market 5" backing plate and use 5.5" pads. Right now I've got Orange, White, and Black hex logic pads but want to try some Lake county and the Meguiars micro fiber pad system. Also I want to try a light cut burgandy pad for the last polishing step.
There are so many products out there and lots of hype around them it is crazy. I try to use bang-for-the-buck stuff and like Meguiars stuff.
A typical process is wash with good soap or Optimum no rinse. dry.
If it hasn't been clayed I'll use clay bar lubricated with quick detailer.
Then Meguiars Ultimate compound with the orange pad at speed 5.5. I love ultimate compound. It is affordable and works well but the speed has to be higher and pressure at 10lbs and even. Work in small sections (2'x2') and don't work it too long. Clean the pad regularly.
UC leaves a slight haze, so then I go to Ultimate polish with white pad. Ultimate polish is harder to use. It is finicky when wiping off and sometimes it seems really hard. a towel damp with quick detailer helps. I use speed 4 and have to be real careful of working it too long or trying to do too big an area.
Right now I seal with Duragloss 111. And after it hazes I'll wipe it off with Duragloss Aquawax These two produce a plasticy wet look. It's nice but I want to go back to more wax look. Some say Duragloss 105 has a softer look. I might try Meguiars #21 sealant, and gold class wax
I am also going to try ColorX for every other week maintenance. It is less aggressive then the ultimate polish and is safer to use.
The idea is that once you do this level of correction, you "shouldn't" have to do it again. The reality is that just looking at our cars causes swirls. A big thing is to learn a good process for washing.
The anal detailer guys have thought about this a lot. And it makes sense after doing all that work to polish the clear coat that just going to the car wash or not thinking about how you wash it will undo all that effort.
Look up things like the 2 bucket method, grit guards,... and see how and why they suggest this system.
The other thing is to be fanatical about the micro fiber towels used that touch the paint. Store them separate, wash them separate, throw them out if they have any grit in them. The final tip is to not hit it with quick detail spray every day. Every time you touch it there is chance to scratch the soft subie clear coat.