About to do a service on my Mr2 spyder and will be changing the spark plugs.
Anyway the issue is which to use. Toyota and auto barn both say to use BKR5EIX-11, but the motor has BKR6EIX-11 in it, the previous owner must of had those installed even thou it was 100% stock when I purchased it.
The only motor mods ive done since owning it is a custom intake (uses a k&n Apollo air filter) which draws air from the left scoop, a full exhaust (4-1 headers, hf cat and custom made cat back with 2.25 inch piping) and stage 1 cams
(8 degree increased duration on both intake and exhaust cams and a 0.020" lift increase on exhaust cam only) plus a piggy back tuned to run it all with increased timing on 98 octane, it also has a thermostatic oil cooler. This has given the motor roughly a 20% boost in Kw at the crank (stock 103Kw now 119-121Kw).
So should I just go replace them with the stock 5 heatrange ones or replace them with the cooler 6 heatrange like it has?
Thanks for any help

our spyder uses BKR5EYA-11. yes I do use copper plugs and the engine runs just fine on them. the 5 is standard so unless you specifically want to run a colder plug to curb any detonation problems.
 
do you find with the cooler plugs that it runs at all odd, a little stumbly and puffs any smoke? if it does you might want to go back to a 5 plug.
 
I also wouldn't run iridiums personally. iridiums and platinium are great, but once you start changing things making more power coppers can sometime be better. sometimes.

I put the standard 5 ones in and it was more responsive but it might of been because they were new, may give the copper a shot