30PSI in one of the cylinders means you're screwed. Your rings are shot. Not sure what the exact compression numbers should be, but usually anything 120PSI and above is safe.

Black smoke equals running rich...too much fuel.

The metallic noise you are hearing are your heat shields for the exhaust. You can get under the car and either rip them out or move them around so they stop rattling.

Go to Jiffy Lube and have them change out your tranny fluid, it might cost all of $30. You also may want to bleed the hydraulic fluid in your clutch system...that is provided you have a hydraulic clutch.