My biggest beef with my '07 Fz is the snatchy throttle,
especially when in a corner in 3rd or 4th above 7k rpm. Re-applying the throttle smoothly is extremely difficult. Well I found out Power commander has a new option that helps the problem and I mean helps not a 100% Fix.
The PCIII usb...
I have them on my '07. Excellent fit and finish as well as a good Y-pipe design.
They come with removable db-killers but I perfer to run them un-corked. There loud but not as loud as the scorpions un-corked.
I have no complaints after 2 seasons of use.
Save your money. Remove the cat pipe and punch out the guts with with a large screwdriver and hammer. It helps to drill out as much of the guts as possible with a fairly large drill bit. Worked out great on my 2007.