If so, who offers it? I'd hate for some thing to happen to my rig, and have AAA tell me they will only cover stock components.

Sometimes your policy already covers up to a certain amount. But it any event, it might be a good idea to fax them receipts of everything so they have it on record and there won't be any question in the event you need to make a claim.

....does the factoid that we mod our rigs for more power raise a red flag? has anyone here ever filed a claim (successfully) and recouped all the mod bits that got jacked up in a crash?

insurance rates as it gives question to the value of the car when modified. Upgraded audio is a different story. Some auto insurance companies defer to home insurance to cover things like belongings and any other aftermarket electronic components installed like satellite radio, navigation, etc. Also, you have to be careful with the auto insurance companies... some will raise your rates when you inform them you've got a modified car, because it changes the OEM performance characteristics. So, you would want to inquire about such insurance as "if I decided to install x,y,z" rather than saying it's already installed.

My friend figured out with the increase in liability due to the modification and then the addition of covering the installed components, he would pay for his turbo and chip in two years by not extending his coverage for modifications (he shopped around and some wouldn't cover it).

more could be purchased after that.

My esurance policy has an add on if you have comp and collision also but not if only liability and comp or collision. Up to about 5K I think you could add.

The other option would be to double insure the vehicle.

Bascally get full coverage for the basics from one company and then get a second policy from one of those collector / show car companies that will asses just the value you want on certain parts. You can probably get them to write just a comp/collision policy that would cover the parts and not the entire car.