...than the sedan?

How do the stock sedan and coupe air inlet systems differ?

How do the stock sedan and coupe exhaust systems differ?

If my eyes didn't deceive me, my sedan appears to have one large cat. Do the coupes have two smaller cats?

 

I guess it has more to do with the ECU being more aggressively tuned for the coupe to squeeze out 20 more HP.

 

I think that's right dude. It's mainly in the ECU: timing, fuel etc. The intake and exhaust could be slightly less restrictive.
As far as I can tell from owning both, there's not much difference in the engines at all. [img]/w3timages/icons/smile.gif[/img]

<font color=green>GSM</font color=green>

 

The coupe's intake is described as "micropolished" in the web info, and the sedan's is not. That may have something to do with it.

The sedan has a single exhaust with twin exhaust tips, and the second tip doesn't open up until about 4,000rpm. The coupe has a dual exhaust system.

The ECU is more aggressively timed (as the coupe requires 91 octane all the time, while the sedan merely recommends it, and can be run on 87 -- not that I would use it).

2003.5 G35 Sedan Desert Platinum/Graphite Premium/Sport/Aero/Nav/Winter

 

don't forget that the coupe has electric cooling fans and the sedan has mechanical / belt driven fan, that's good for a few horses.