I have a 1999 E430 (aka W2100). I have about 145,000 miles. When I brought it in for service, the mechanic told me I should replace my 2 motor mounts. He said during the test drive he felt they were worn. He demonstrated this when I got there by showing me how much the engine was torquing when he pressed the gas while in drive (while pressing the brake). I saw that the engine was torquing (i.e lifting to one side) about 1.25" when he hit the gas.

Two questions.
Does what he show me indicative of worn engine mounts?
What's the downside of not changing the mounts right now?