To add to the nearly 2 year old thread....

This is as I've stated all along.

If you're racing on the track, you may gain a couple thousandths.
If you're "paper racing" your numbers may look better than your buddies.

Your assdyno won't really be able to tell.

 

An oldie but goody! As for the '*** dyno' telling the difference, I commented way back that I get 15% more low/mid range torque with my 2-into-1, compared with my previous TDs - that is on a real dyno! Bike is much sweeter running and quicker all round, on the road. A significantly better and nicer bike.