I got quotes to replace glow plugs in my 95 E300D in the range of $400 to $600. All quotes required the R/R of the intake manifold to gain access to the plugs. That's where the labor cost comes in. After extensive research, and finding out there is a technique to replace them without removing the intake manifold, I did the job myself. It told me about 5 hours, but 3 hours was spend on getting the 6th plug out (Next to oilfilter) You will need to remove the crossover manifold (From air filter to intake manifold) Lossen bolts and disconnect at joint to intake manifold (O-ring might be tight) This will give you access to 5 plugs. (A note, disconnet all wiring harnesses and move away to avoid damage) Pull off connector to glow plugs, use 10MM? deep socket with universal joint and 10 and 8 inch extension. You can use a 1/4 with the front 5 plugs, but you must use 1/8 extensions with the 6th plug. It also helps if you have small hands with long fingers. If you take it easy, you will loossn the carbon on the tips to remove from the head. You will need to take a phillips screw driver about the same diameter as the tip of the glow plug, cut it off about 1/4 inch longer then a glow plug, and cut the handle off to about 1/2 inch. Use this to insert into the glow plug hole to remove excess carbon build up inside of cylinder/head. This will allow you to start the new glow plugs with no problem. Put everything back together. A few other things, there is a resonator valve on the bottem of the crossover which has a vaccum line attached. You will want to remove and clean while you have access to it, it a easy job. This will work on all 95-97 models. The 98 & 99 with turbo make be a little different. In the end, a $1000 is high, but it is a challeging job for a rookie. I can replace the glow plugs in my 85 in about 1 hour. Good luck if you try this yourself.