sliq wrote:what difference would the sound be if you were to buy an aftermarket muffler and install that alone.. then changing the extractors and midpipe?
I wouldn't bother with extractors unless you are chasing the last little bit of power, the standard set up is ok.
Make sure that the exhaust shop can put you in touch with someone who has the set up they are recommending as there are plently of droning, flat or raspy set ups around and I learnt the hard way that you can spend heaps chasing down a good, efficient set up.
Otherwise just turnup to a club day and find a set up that you like.It is really important that it doesn't drone, many Mx5's do from around 2700-3300 rpm and that will drive you batty on the highway
If you are going to start with a muffler make sure it is the diameter that you will want to use later(ussually 2 1/4 inch) and a freflow design so that it is not a restriction when you later decide to complete the exhaust.
My figures show that there is some gains from a good catback over a standard one , so go for it!
Good luck,
Peter
.Now ND2 Roadster prev NC2 Recaro's ,BBS wheels,full exhaust, Tiens NA 1.6.NA 1.8 LE(106RWKW)NC1,NC2.ND 1.5 .