which diameter have the JDM EP3?
Muffler & b-pipe
the JDM header & cat have 54mm (cat exit)

and
does the DC5 b-pipe fit on EP3?
the DC5 have 54mm b-pipe?

thanks!

 

I'm not sure about the JDM EP3 b-pipe but I'm 90% sure that the muffler is exactly the same as the USDM EP3 muffler. Our stock muffler actually breathes really well up to 300 hp, it's our stock b-pipe that's really restrictive. I do know that the USDM RSX-S b-pipe will fit on an EP3 but you will also need a RSX-S header and cat or a RSX-S race header. The RSX muffler will not fit without modification, the hangers are different and the tip will stick out too much for our cars. So to recap, possible exhaust combinations for an EP3:

RSX-S stock header + RSX-S cat + RSX-S b-pipe + EP3 muffler or...
RSX-S race header + RSX-S b-pipe + EP3 muffler

FYI, the 05-06 RSX-S came with a bigger b-pipe. I believe the 02-04 RSX-S came with a 2" diameter b-pipe and the 05-06 RSX-S came with a 2.25" diameter b-pipe.

 

I just realized that you're in europe so I assume that you have a type-r. Everything I said applies to the US/Canadian EP3 and RSX, sorry. It might apply to your car also but I'm not sure.

 

The OEM catback on EUDM EP3 Type-R's is somewhere around 1,7-1,8", would imagine that the JDM one is a little bit bigger. But if you're going to change it why not buy an aftermarket catback immediately?