We've talked about them more on another forum and on FB groups. Many here are members on the others. Yea, they are just for the cross bikes. But I'll tell you what I can. I've had mine, the original prototypes, installed since last November. Played around with a lot of with and without tank lift during the past 7 months and have learned a few things.
It's kind of funny for me on the performance topic because it wasn't a design goal for me. Wanted more space under the tank to play around with the intake setup and to give the tank a slightly more aggressive profile. I've been reluctant from the get go when we let the first 5-6 sets out last year and received anecdotal reports of possible performance improvement. Performance gain and claims, for me, has been a pleasant surprise but something I've avoided emphasizing.
The first dyno with them I believe was my bike in April at KevinX's shop in Florida. This was with cams, PCV, Lloyd air filter, timing wheel at +6, RCX mufflers, tank lift spacers and local 93 octane with up to 10% ethanol. He said he saw a couple of hp gain. He said he wasn't sure if it the filter was generally getting more air, or just more are when stationary in his enclosed trailer, a couple of fans supplying cooling air. I'm pretty sure there's a couple other dynos out there now as some have mentioned getting them installed at the time of cam swap and tune. But I haven't received any info yet.
I think that with the spring and summer rallies, the major tuners stay swamped with work, whether at home or on the road. I honestly don't think any have the time to give up half a day to do a proper dyno before and after comparison, tuning for each cylinder, cool off times, etc. Maybe over the winter something like that can be done by someone.
My educated guess based on my 7 months with them is that, when combined with the Lloydz air filter, is that the tank lift improves throttle response. I'm thinking it's sort of along the lines of adding a cold air intake on a car. Typically people feel a difference when driving around town. Maybe there's a couple hp way up on top, maybe not. But mostly it's just a throttle response improvement they feel, due to better flow dynamics between the filter and the throttle body, accompanied by a change in intake sound. Those aren't things that show up on a dyno sheet. Then there's Kyle who mentioned that he liked the way the lift spacers snugged up the tank fit.
In the adsence of sufficient hard data, we are left with trends interpreted by those who know these bikes well. I don't have anything more to offer at this time. And rather than answering a half dozen PMs a week asking how to get them, it just seemed easier to post it as a thread.