BB AP1, although upgrading exaust system is recommended with the use of Mugen ECU in the spec sheet, you can still benefit well even if your exaust system is in stock form.

What made me decide purchasing the Mugen ECU while back (9 monthes ago) is that I can get consistent power delivery with Mugen ECU. Stock ECU seems to get scared easily and it can reduce power noticeably. Obvious reason for the is to safeguard as much as possible for the engine that needs to be revved past 6K to 9k redline. Believe me, as you build more seat time with your car, you will easily notice when ECU is holding back on power.
As soon as I received the Mugen ECU, I found out that there is some change in the fuel map which I thought was a real treat. As soon as I put it in, I started to notice how better it pulled from stand still and the power delivery seems to be pretty much consistent.
Please bear in mind that the performance gain is sort of subtle but enough to put some grin on your face, so do not start to have high expectation.

About other Japanese tuning company offering ECU services,
most of these company offer ECU service under trade-in term,
which means you are bringing your own ECU to have it modded and also most likely your car as well.
Amuse is no different, they do not sell separate stand alone ECU like Mugen or Spoons but they need you to send your own ECU to have it altered. When the idea of doing ECU for US spec S2000 was suggested, the president of AMUSE sort of declined. Since Japanese and US engine perform differently, they do not want any trouble from using there ECU and totally screw up your car. Although you can take total responsiblity and consequences on your own, but they still don't want to see anything go wrong from using their services.

So stick with Mugen for ECU. With Mugen ECU, I observed no irregular behavior. Everything seems normal but better.

 

Would the Mugen ECU work with 91 octane? There is no more 92 octane here, of course there is always octane booster, but I don't want to have to use that on a week to week basis.

 

[QUOTE]Originally posted by F2ZeroC
[B]Would the Mugen ECU work with 91 octane?

 

can the Mugen Ecu be used w/ a VAFC? Would it be effective? Would this be a way to use the Toda cams w/ the Mugen ECU?

 

in that case you're better off IMHO with something like the AEM EMS where you can actually do the re-programming to fit different components.

 

Wow this thread is almost a year long. I have an AEM CAI and a HKS Hiper exhaust, it should be ok to use the Mugen ECU. Yes?

Thanks

 

Yes it should.

I have the Mugen ecu and found the car is smoother below 4k rpm with more torque and the tailpipe always stayed clean. The oil seemed to stay cleaner as a consequence as well.

I got tired of filling with 100 octane and switched back to the stock ecu. The pipe again is very sooty and so I switched back to the Mugen ecu but mixed 1/2 100 octane with 91 octane. The car runs fine and I noticed the better running each time I went from stock to Mugen.

I think I will try mixing 60/40 91octane/100octane in the future and see how it goes.