Sorry to hear about the big laundry list but those are all common wear items.
The shop probably did a scan and found the gas cap error. I've changed at least 3 gas caps over the years on German cars, countless control arms and valve cover gaskets on 2.
A bad coolant leak could down the transmission onto the exhaust pipes then easily run down the pipes to exhaust canisters, especially if you park the car on an incline (like in your sig).
The noise from the front and shaking is a pretty good indication that the front control arms are shot.
Straight lines are for fast cars...turns are for fast drivers
'04 M3 - track
'06 650i Cab - daily driver
'02 Highlander - kid hauler
'01 330Ci - winter beater
Last edited by Yorgi; 01-05-2013 at 06:39 PM.