You are probably right. Are you happy with the sound? Did it get any louder, I would love to have the resources to do rear wheel dyno runs on all these things and see the difference if any. Thanks GRIP
Performance increase if any would be marginal. In order to show real performance increase, you would need headers, and a true dual catback exhaust from one end to the other. And then, you would need to open up the air intake system, by finding a location to add a second air box and the necessary Y piping. The 300Z had a dual head Jim Wolf to increase airflow directly replacing the stock air box, but there ain't much room in the MO. And then, the ECU would need to be reprogrammed in order to take advantage of the better flowing capacity of the system. Then, a dyno run would probably show some interesting numbers. Otherwise, why bother for 5 HPs over 245? I mean, what does a 2% improvement show in a dyno run?
Dyno runs are pretty far from realistic numbers. The conditions are very different from real world. And you're telling me you wouldn't want better throttle response, even if it only comes from 5hp over 245?
Honestly, I do not use the already existing 245 so I really couldn't care less for 5 more... If I want to use and abuse a ride, I'll get a specifically designed one for the job. The MO has a 16+ to 1 weight/power ratio and it's standing way too high for any serious cornering. My kind of fun is usually a ride under 10 to 1 w/p ratio.
To get there with a MO, you would need to add 155 hp to the stock ones so yes, I still sincerely believe that your throttle response increase feeling is going to your ears and not to your wheels. Been there, done that. I've seen (and paid for) what it takes to do the job properly and a little piece of tubing here and there usually makes the power inversely proportional to the amount of noise.
But I do agree with you that any car without a muffler does sound much faster, and all Neon, Golf or Civic ... owners do know about this fact.