the $38k price is in Japan. I'm not sure what a JDM STi goes for but the price difference might be much different. I know that in the UK an STi is near $40k with the VAT taxes and such.
another reason to opt for the Mugen Si is for tax purposes. in Japan automotive taxes are based on engine displacement.
I'm willing to bet that the Si will get slightly better gas milage than an STi. with gas prices what they are in Japan that would add up over the years.
yet another reason is that the Mugen Si is a true limited edition with only 300 available.
and finally, there are those who are die hard Honda-philes and will opt for the Si for that reason alone.
as a former Honda owner I can understand. I wouldn't necessarily make the same decision, but I understand....
Well, Subaru has removed the "old-skool" Impreza from their site, but the new hatch in S-GT trim goes for about 2.5million yen, varying according to transmission and packages. That translates to 20,000 dollars... Wish I had old STi info, but this is interesting too.