Sparkplug problems

My Toyota garage says that if I replace the spark plugs with 'Laser Iridium Premium NGK IFR6T11' they will cause problems - what problems - not stated.

These are not the recommended plugs, but I have already bought them from another dealer. email to the manufacturer in the USA stated that these plugs were often used by Toyota - again not specific enough regarding use in my RAV4 (three-door version 2004; milage=40,000). Can you say what problems these plugs will cause if I go ahead and ask the dealership to use them? Is the garage just trying to frighten me into using their own brand?

Asked on 6 January 2013 by BeKiRa

Answered by Honest John
Pretty simple answer: do what your garage tells you to do.
Similar questions
My 2019 Honda CR-V EX is due a service. It's done 53k miles, being serviced regularly. The franchised dealer recommends replacing the fuel filter and the spark plugs. I've used Shell V-Power fuel since...
I have a 30,000 mile 2018 BMW X2. How often should I change the spark plugs ?
How long should a set of spark plugs last?