as for the tach run a search on "cigarette". i have the same exact year and model as you do. i'm only going to say that trust everyone here, some of us have had our cars since they came from the factory we're all here about our cars and hoping to keep them running for as long as possibile. i have one question about the cone air filter: how much does it weigh? the stock filter weighs 1lb and 1 or 2 ounces i believe, i'll have to check i have one in the garage. but that also shows the about of paper and thickness it has to keep these engines sucking in air. personally i'm staying with my stock air filter its the reason my car has been around so long.
just my .02
-Steven

__________________
1982 300D Turbo 203K silver
Need to fix these leaks badly