I wanted to know what's up with the denso iridium spark plugs for a GS 300? Does anyone know the benefits and/or performance increase from these spark plugs?

 

gs comes with denso iridium plugs already.

 

not the gs300. according to the owner's manual for the 300 there's platinum tip plugs. but the 400 has the denso iridium.

 

which year gs300 are you talking about? I have 01 gs300 and as far as I remember reading the manual that it came with denso plugs. I will check again tonight but I am pretty sure. I did change my plugs to torque masters though.

 

I just checked my user manual for specification for 01 gs300 and it is denso iridium spark plugs for both gs430 and gs300.
so if yours is at least 01gs3 then you should have denso plugs already. If not, well I don't know if denso or tm plugs be better or not. good luck.
P.S. I did have good experience with my tm plugs but some cl member didn't so check with other members about the plugs.
hope this helps

 

I have 98 gs300 with 50,000 and just replaced my stock ngk with the denso iridium. Igt seems to idle better and midway through the rpm range seems to accelerate a tad better. I did this myself and if I had to do it again I would the dealer do it! It was a payne, you must remove the whole throttle body and the plugs wires are ina precarious position. All in All I would still upgrade to the denso plugs!