There are 2 types:

1) 2 Trailing (top) plugs, and
2) 2 Leading (lower) plugs.

NGK's are recommend.

1st question: which coil (one is next to the battery/fender and the other next to the strut/firewall/fender) is for the leading plugs and which one is for the trailing plugs ?

Note: This is for a N/A FC.

2nd question: What happens if you use 4 leading plugs ?, any ill effects ?, power loss ??

I searched the archive, but it is empty.

TIA !!

 

I have a 3rd gen, so i can't answer about the coils, but i can the plugs. Don't use 4 leading plugs. They are of temperature 7 and running these in the training holes can cause detonation. Most people run all trailing plugs (Temperature 9) to avoid unnecessary detonation.
~Tom

 

the one by the battery is the leading and you can use 9's (trailing plugs) more cooler that the leading which are the same plugs but a hotter range (7's). i run 9's all around but i have a TII.