as far as i know the mugen Si offers no performance increase over the regular Si. The suspension is better, but most people ditch the stock suspension anyway. This is $30k for a civic. The whole point of the Civic line is performance for great value. When you get up to $30k that is territory for other cars like the s2000, 350z, G35, Evo, Sti, etc. I've had an integra type R and it was not just an integra, it was a completely different car. The chassis was stiffened, the engine had more power, the braking was improved, it was lighter, the interior was awesome. That car was $24k new, that's value to me. The mugen Si is like a wannabe type R. Don't get me wrong it seems like a great car, but I'd like to see some improved performance numbers before I shell out $30k.

 

i've had s2000's, a type R, and now an evo. The build quality on a Honda is a whole lot better than anything Mitsubishi has ever put out. The only reason I still have an Evo is the resale value on it sucks. I got the Evo thinking it would be a good daily driver, but just b/c it has 4 doors don't let it fool you. It's stiff and bumpy and it gets horrible gas mileage. I would rather have an Si sedan than an Evo but I just don't think it's worth the negative equity. I'm hoping when the Evo X comes people will be looking for the older Evo's due to their mod friendliness and maybe the value won't be so depreciated.
With only 500 mugen Si's being available I would be surprised if all dealers did a "market adjustment" of atleast $5000 dollars.
The ITR is a great car, it wasn't just another integra. Everything was upgraded on the ITR (braking, engine, suspension, chassis) where it only seems suspension is upgraded on the mugen Si. Still a good looking car though.

 

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depending if your a daily driver, highway miles arent always the best, si sometimes has oil problems with highway

 

o2 sensor also has some problems, other than that its a gr8 car