I treated my new Crossfire SRT-6 roadster this weekend. The passenger side was OK but there was rust in the driver's side door. Both sides were damp to the touch. I've had this car a little over a month and it only has 406 miles on it. I used POR-15 as recommended by Andrew. I used the black POR-15 Super Starter Kit. It was $17.25 and, with shipping, the final cost was an even $24.

Here are the steps I followed:

1. Grab the rubber trim and peel it downwards. That seemed to pop it out easier than pulling straight back on it.
2. Mix 1 part Marine Clean with 5 parts water. You don't need much.
3. Using a small sponge, scrub the groove in the door.
4. Place a drip tray on the ground where the door meets the body of the car to catch the runoff. These chemicals are nasty so don't let them run everywhere.
4. Using a spray bottle filled with tap water, rinse the cleaner out of the groove.
5. Take a small dowel, wrap a microfiber towel around it, and dry the groove as best you can.
6. Blow the rest of the water out with a shop vac, air compressor, whatever.
7. Tightly fold a piece of 400 grit sandpaper and lightly scuff the painted surface in the groove. You won't be able to scuff it all because it's a tight space but do what you can. Rinse out the grit you scuff off with water, dry with a towel, and blow out the remaining water.
8. With the supplied paint brush (not the spongy foam brush), brush on the Metal Ready. Again, make sure your drip pan is there to catch the runoff.
9. The instructions say to keep it wet with Metal Ready for 15-20 minutes. I split the difference and set a timer for 17 minutes. Once every 5 minutes, give it another coat until the timer goes off.
10. Rinse with water, dry with a towel, and blow out the remaining water.
11. Clean the brush with water (the Metal Ready will stain it blue but do the best you can).
12. Mask off the groove with blue painter's tape.
13. Using the brush, paint on the POR-15. You can use the sponge brush but I found the regular brush works best.
14. The instructions say it will dry in 2-5 hours. I waited 3 hours and applied another coat. The instructions don't expressly say it but they seem to imply that you want to apply the second coat when the first is tacky but not completely dry. Also, use a clean brush if you can. I reused the brush I used for the first coat but the POR-15 had hardened the bristles. It was still usable but a new one would have worked better.
15. Wait a full 5 hours for the second coat to dry.
16. Remove the masking tape. If some of the POR-15 wicked under the tape, you may be able to scratch it off with a fingernail. If a large amount wicked under the tape, forget it. If you try to remove it, it will take the paint with it.
17. To reinstall the rubber trim, lie on your back looking up at the bottom of the open door. Put the bottom of the rubber trim into the groove in the door. With some effort, it will snap in. When you've done the whole door, sit up and push the top half of the trim into the groove. You'll see three grooves in the top of the trim piece. All three should be inside the door. Unfortunately, even after a whole lot of pushing, I was only able to get at most two grooves into the door.

Issues and things I learned:

1. POR-15 will wick under the tape if you're not careful. I was able to get most of it off but a noticeable amount of it wicked through the U-shaped drain port where the bottom of the door curves upward. It's not visible unless you're lying under the open door and it doesn't interfere with the operation of the door (i.e. it doesn't hit the body of the car when the door closes). It's not a big deal but it's untidy. I'd be curious to know how others avoided this problem.

2. If you get POR-15 somewhere you don't want it, it wipes off easily as long as it's still wet. Once it's dry, you're hosed.

3. I'd really like to know how to get the rubber weather stripping fully reinstalled. I pushed and pushed until my fingers ached and it's in there well enough that it's not coming out but it's not in there as tightly as the sections installed by the factory. There must be some special tool or technique for this. I can't believe guys in auto body shops actually spend two hours like I did, grunting and pushing this stuff with their fingers. Any suggestions would be appreciated.