GS300 Spark plugs

[BristolBrian]

I've just bought a rather lovely 2005 GS300 SE which has been gorgeously looked after by the couple I bought it from. It's got full Lexus history except for the last 3 services which were done by an independent, and I can't find any evidence of the spark plugs for at least the last 3 years. I'm tempted to change them even though the car seems to be running fine. What's the collective wisdom on this? Worthwhile or waste of money?

While I'm at it, the plugs look to be about £20-£25 each - rockauto.com seems to be offering 6 delivered Denso 3473's for £58. Are these guys reputable? There is a note against the plug saying "Part is designed for US, CA Market vehicles" - if it's the same stock number, surely it'll be the same plug as over here?

Any advice appreciated!

[Surebet]

I'm a great believer in " don't fix something that isn't broken". If the car is going well and fuel economy is OK then leave well alone. Nothing worse than trying to improve something and then creating a bigger problem. I've just got rid of a 15 year old Mercedes (had since new), spark plugs never done and still with original pads and discs, albeit only 55k miles on clock. If I had followed Mercedes service plan all these things would have been done. The car was more responsive and better fuel economy than the car I'm driving now, so if your car is giving you trouble free motoring leave well alone, you'll soon be aware if spark plugs are starting to fail. From American web sites, they run their Lexus cars for 100k miles before renewing spark plugs.

[messi]

What's the mileage on the car? Also you should be using irridum sparkplugs made my Denso. I buy from rock Auto myself and it's cheaper but quality parts. 

[BristolBrian]

Thanks folks - so rockauto is credible, but I think I will leave them as is, and just change them when they start to deteriorate (with Denso Iridiums). The car is 2005 with 85k, so I guess the plugs were last changed at the 6year/60k or 8 year/80k services done by Lexus roughly 7 or 5 years ago (although only 25-30k miles ago).