I did mine a few months ago..

I didn't have to take the exhaust off as noted. I did take on the driver's side the airduct and side plastic panel off- near straight access to the front block bolts. The rears an extension through the wheel well @ tie-rods.
I think taking the brackets loose and out of the way really helps. I had an off-set socket thing for the top bolts- you can torque them that way too. Stahlwille or someone makes them nice at $40 but got a knock-off on ebay for $12.
It was pretty easy except the I would highly suggest anyone to power wash and degrease repeatedly the lower engine area before working on it.

If you've got the exhaust pipe out- it's a good time to replace the PS return hoses!! Check the PS pump for leaks as makes easier access of those mounting bolts too.
I think every thing I've touched on the e420- I've had to remove something else to get at it or put it back... just limited space.

Michael