I am sure a lot of money had been spent on the car. That is why the OP is facing a dilemma. Personally I like to sort out the drive train before investing on paint, suspension or other cosmetics stuffs. You get a feel on the engine and tranny, say after 10k miles, then you invest on other stuffs. The car does not burn 1 qt oil per 180 miles overnight. If it were me, I would not spend the money on paint work and the rest with a questionable engine. Enough said, I am only offering an opinion, it is not my money.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.