Auto body repair & detailing: Hard rear end collision advice, rear quarter panels, mercedes ml320

Question
Hi Ken,

I have a 1999 BMW 323 convertible and was recently rear-ended on the freeway. I was stopped, the car that hit me was a Mercedes ML320 SUV, and I estimate it hit me going at least 20 MPH. I then hit the car in front of me, which hit the car in front of it. Luckily no major injuries. Damages I can see immediately to my car:
--Roll-over system engaged (roll-bars ejected)
--Trunk smashed-in significantly (won't close, bent in many places)
--Rear lights displaced
--Muffler pushed down almost to ground
--Rear quarter panels buckled
--Rear bumper pushed forward to tires, other parts knocked off, bent, smashed
--Front bumper dented
--Some misalignment of convertible storage doors
--No vehicle electrical power

My questions:
--What do you recommend I look for in a body shop? I am not liable for the costs, but I want quality work done.
--Any tips to evaluate the car after I get it back?
--Any specific questions I should ask the body shop regarding repair procedures?
--Any tips on dealing with the liable driver's insurance company?
--Could you make a completely unofficial guess at a damage cost estimate?

Thanks for any advice on any of these!
Jason

Answer
Look for a body shop that is at dealership preferably a BMW dealership. They must have a computerized Frame rack system and a down draft bake booth for baking the paint. Also technicians that are ASE certified. When you get your car back make sure the paint matches and that the body panels are aligned right. Ask the repair facility what they warranty and if they will use new or used parts. Used part are OK if they are quality parts. Tell the insurance company that you want your car repaired to pre-accident condition period. And if it is not to your liking you will not accept it. I would guess the cost at $8000 dollars.
              Thank you for the question and good luck.
              Ken