MAYAman,

The real question you have to ask is...

"Is it worth it to ME to sell my Limited and do the mods to the SRT6?"

As people have stated, you can get the motorized rear spoiler, and replace the fixed one. Don't know how much a salvaged wing mechanism would cost or how much the dealer would charge to put it in. Also, the rear spoiler controls are in the body control module. If you had a module from a wrecked limited version, it should be able to recognize the wing. I don't know if that rear spoiler circuit wiring actually exists in the SRT6, so that would be one thing to look into before making your decision, because if it's not there.. you would have to run two wires for the motor and then the existing body control module might work. If the wiring is in place on the SRT6 (I can check that for you) then the body control module MAY work just fine. I'd have to put a meter or test light on the wires (assuming they are present) and see if the meter or test light come on at speed. Also you would be missing the manual controls for the rear spoiler and those would have to be installed also (there is a dummy switch location on the SRT6).

As to the spring rate and lowering... I would try and sell your Limited with your springs in it and then get a stiffer but lower kit for the SRT6. The rest of the suspension is already tuned pretty good shocks (dampers) and sway bars.

As to the front, I don't know anything about the StarTech unit you have. I would call StarTech and ask them. They should be able to help you out.

Good luck!