Probably this bit from the '00-'08 service manual.

 

What's the correct part number for 04-05 coils?

Same expensive price as 00-03 coils?

 

04-05 are half the price of 00-03, hence why I replaced my failed AP1 coils with 04-05 units

 

Well, as long as they don't damage other things in the future (like the ECU), then the savings is worth it.

 

That’s it man

 

I have the NGKs in mine right now which cost me $130 for all 4 That is less than one Denso 00-03 coil pack from Honda. A number of us on here run the NGK. But then one person bought the same part number NGK and they do not fit, we have not figured out what happened there yet. But you can also just order the Densos from Honda for the 04-05 which are still half price of the 00-03 units.

The problem with the 00-03 units are they were spec'd only for the S2k and hence cost way more to make since lower volumes. So Honda is going to sell them at that higher price. The 04-05s are shared with other Hondas and thus, higher volumes, lower pricing.

 

I wonder if denso started using the same plastic mold for 04-05 and 06-09, the only difference being part number and absence or presence of the resistor internally....?

 

Don't you think that is more than enough speculating going on here especially in this thread?

 

No, if I did I wouldn't have posted. Considering no sufficient explanation has been offered yet, I'm pretty sure we're left to speculate.

 

Speculation can be a form of brainstorming. It may spark someone elses realization.

Obv can become unproductive. But not sure we're there yet.