Ensure your Bowdin cable is adjusted, and your fluid/filter dresh enough. I personally run Red Line Synthetic ATF in all my Benzes
Pirelli P6000s suck. Worn snow tires are quieter.
The airbox is a waste under 6.0 litres of displacement, perhaps even 6.5
PAD chip did nothing for my car-Jims 500E (unchipped) and I dragraced, and he was glued to my bumper the length of the track. Both are early '92s. Only reason I beat him was I got him out of the hole-got lucky and got the jump on him. I'm thinking I'd have rather spent the $$ on a Time Valve Y-pipe
Again, just my opinion, and 2% of a buck