hello everyone

i would like to start off saying that i now longer have a 99 gtp (burned in my driveway) and now have an 01. I just bought the car today and have a couple questions. first the low engine cooling light is on but the engine coolant container is almost full? im guessing probably a faulty sensor but im not sure. also the tcs off light is on as well as the abs sensor. im guessing its a wheel sensor but how can you tell which wheel it is? The car also has some mods. it has a 3.4 pulley, msd ignition coils (the middle is still stock) new spark plug wires,(not sure about plugs) an intense racing prm, C.A.I and a new muffler and tips on the car. everything up from the muffler looks old so im guessing its stock. Im new to all this modding stuff but from what it looks like is that you also need a downpipe and im not sure if this one has it or not.(i just got the car tonight and haven't really been able to crawl underneath it to check it out but some insight would be helpfull.

Thanks