I am experiencing a rougher ride as of late. It makes a loud clunk when i hit any bump in the road. Ive had people tell me its the suspension, tires, bearings, bushings, and pep boys just said it was the plastic under carriage. I can't really afford to replace all at once so i was wondering if there was a way to determine for sure what is the most serious issue? Also now it feels like its shifting harder and the engine is starting to feel sluggish..... suggestions?

 

It's a 2010 ford mustang v6 coupe (manual )

 

How many miles are on the car?