My 2000 chrysler 300m smeells of gas all the time but runs great when i checked under the hood no visual leaks but can smell it realy strong on the passenger side of rear of motor

Have the purge system tested, and the regulator diaphragm looked at. also the lines, especially the quick disconnect lines up near the engine. You smell gas, but as the engine heats up, the gasoline evaporates and you don't see where it is coming from. This is dangerous in any case, not to mention smelly. The regulator is located in back of the engine (on top) near the throttle body. (just underneath it).
Start the car and let it run for a couple of minutes. Stop the car, and using a flashlight and a good retractable mechanic's mirror, take a look for wetness.
if the regulator (a small, flat inch and a half disk attached to the fuel line) is wet. have it replaced right away. The purge system canister can usually be tested by a good mechanic with the right equipment. You and I usually cannot do this ourselves.