oil ???????s and then some

99GTP ive had it now for about 2 months and going to get the oil changed.. what type of oil and dont know what was in it before? im thinking syn.oil but could be wrong......... the other ? is im going up to autozone to get plugs/wires/t-stat.... i want colder plugs and a 180 stat just need to know what plugs and numbers

Avoid Bosch plugs like the plague, trust me on this. Autolite are what most modded guys on here run. Oil is a personal choice, but many GTP owners like synthetics. Be wary that if your car has any oil leaks currently, switching to synthetic will make them worse.

what brand of oil is the best for GTPs,and any plug numbers remember i want colder running plugs

I had autolite 605's in my GTP last year, they seemed alright. The 605's are 1 range colder and the 104's are two.

Now I have iridium NGK's which seem to be good. the tr6ix I believe are 1 step colder and the tr55is are a half step colder than stock, but I dont remember exactly.

I just put in what Bob told me to. He's a genius when it comes to things like that.

I have seen great things with NGK iridiums in boosted cars. I was getting horrible spark blow-out until I put in my NGK iridiums and it runs great now. As far as what oil works best in your cars, I am not sure. I use a heavy weight Royal Purple in my VR4 and have had no complaints thus far. Agian, my car is boosted like yours but is not a GTP so don't take what I say as the rule.