Was at the bone yard the other day and searched for a an underhood insullation panel. No luck with a Benz/Lexus-they didn't have any. But that's OK-I took one off of a 1994 Buick LeSabre and installed it under the hood of my '89 245. The shape of the piece seems to be a great fit. I also took the 2" plugs that fasten it to the hood (8-10 of 'em). Coincidentally the plugs fit the pre drilled holes on the 245. I just needed to find the holes under the padding via a tiny screwdriver before pressing the fastener to the hood. In addition, I put maybe 12 globs of silicon on the frame of the hood for additional fastening.

The difference is REMARKABLE. I would guess that the engine sounds 50% quieter at idle in the driveway and 33%+ quieter on the road. It was well worth doing this and the boneyard gave it to me. DOn't see any difference (so far) witth he temperature via the sensor. The hood is as cool as can be as well. I'll keep everyone posted if anything changes, but this looks like our inexpensive solution! Thanks Buick!