I may not own a Xfire yet, so I haven't had a chance to 'feel' the 'lag' yet.

But I'm going to tell you from my experience driving turbo cars for many years and a carburated bike, that 4/10ths of a second you can feel. Why do you think so many people complain about 'turbo lag'? That can be cut to less than 4/10ths of a second and it's still noticable.

As someone previously mentioned, if you are heel toe shifting, then 4/10ths is a BIG deal.

Also, if this concept didn't work for some to change the 'feel', then why are throttle cams sold by the ton for bikes?

I think at this point there seems to be a perceived debate over whether or not it enhances performance. That has been imperically proved wrong. The manufacturer doesn't even claim imporved performance.

Basically it boils down to if you like the feel with it, then it's worth the money. If you can train your foot to drive differently and compensate for it, then the money isn't worth it.

Hands, I think you have done a good job of illustrating to all of us what it does and dosen't do. At this point it is up to the consumer to make his/her own educated decision as to whether they want to purchase one or not.