Sorry for the late reply, the plug the guy put in before I bought the car just got messed up and its leaking air. Now I need to buy a new tire because they won't fix a tire where its worn out on the sides.Listen to TexFinn's advice.
It's most likely not the cheapo tires themselves. There's a reason the PO was running cheapo tires. The PO may have been too cheapo to properly maintain the car, including its wheel alignment & suspension components. Possibly also too cheapo to properly maintain the transmission. Verify transmission fluid level, condition & when last replaced. Then check if tranny is covered with years of gunk. Heat-related issues, Modulator and/or wiring connections could be voicing their displeasure.
The car has 151K miles. If these systems haven't been maintained, they are probably all due. Get it inspected by someone who knows Benz.
If the car bounces on a speed bump or anything the shocks squeak. The guy before me was a cheap I am thinking now. :/