W123

Hi all and happy holidays. I have read all the posts concerning my make and model and have gained a tremendous amount of knowledge through this great resource. One thing that puzzles me is all the remarks about exhaust smoke. I don't know if I am just lucky but my 300D never spews any smoke upon start-up or running. The only time I can see anything remotely resembling smoke is when I really get on it at night and look at the headlights of the guy behind me. It is just about invisible during the day.

I've been struggling with a problem of my engine not reaching optimal engine temp under normal driving conditions (summer driving in the mountains always does the trick). On my normal, mostly flat drive to work I barely maintain 165 degrees in winter temps of around 40-50 with heaters going (which just barely keep me warm). Here are my specs:

The radio in my 84' 300d is a Becker Grand Prix Electronic and when I start the vehicle the radio comes on, then cut in and out every 2 seconds consistently. Now if I turn the radio power button off, then turn it back on a couple seconds later it works fine. I want to stay original, any advise? Thanks.

I need to buy all new tires and found Falken Sincera SN-828 175/70R14 tires for only $49 each. These tires have good ratings compared to other tires available on discounttire.com but wondered if anyone else has experience with them on these cars as they are very inexpensive. What tires and size do you recommend for this car?