I have owned 2 stock 650Ls for a total of 9 years and just completed Dave's Mods and the rest of the uncorking process for the 1st time. Dave's Mods, smog block off kit, K&N filter, and tossed the snorkle. Here are my observations: After YEARS of fighting the cold-natured beast and never knowing for sure if it was going to start in the morning or if I would have to push it off, she now fires right up in an instant and is ready to ride in a minute or two - even on cold mornings. HALLELUJAH!!! This alone is reason enough to do the mods in my opinion. Shame on Honda for giving us our Pigs in such a sorry state. How will we ever start our bikes in say... 2025 if the smog nazis have their way? If you are expecting MAJOR changes in performance you will be disappointed, but the gain IS noticeable. Throttle response is much improved and the bike feels and sounds as if it isn't working nearly as hard to do the same things. On backroads it is now possible to just leave it in 5th gear and ride at almost any speed no matter what comes your way. Need to slow for a curve or climb a long incline? Don't down-shift, just roll on a little more throttle and feel the engine "chug" right along. Need to blow around that chicken truck? Just whack the throttle in almost any gear at any speed and she will happily comply. In the dirt there is more "grunt" for the really tough stuff and the engine seems cooler too. I have read that 90% of the engine "popping" goes away with the smog pump.... ALL OF THE POPPING and other funny little noises on deceleration are gone from my bike - TOTALLY as far as I can tell. Another single reason good enough to warrant doing the Mods. I have never kept up with fuel economy and miles per gallon, but I have put almost 700 miles on her (in only 2 days ) since the mods and have noticed no major loss in fuel mileage. I would gladly give up a few MPG though if that is what it costs me. I believe the gains will mostly offset any losses because it now takes less throttle to do the same job. Those who complain about a loss of MPG probably can't control their right wrist. A friend, who did his mods together with me, says his XRL got well over 50 MPG on a 300 mile ride we took last Sunday. There is no excuse important enough not to do these simple, inexpensive mods. Thanks Dave! Cheers!