I've got one!
I've got one of Luis' first gen shifters and and Rex is correct...Not a bolt on installation! You have to disassemble the trans and basically rebuild it. It is not out of the realm of possibility for someone with above average mechanical skills and experience if being installed on a rear engine trike.
My installation has been stalled by several factors. First, in all major projects, Life gets in the way. Secondly, my build is a front engine design similar to Rex's so I had to flip the ring gear to get proper rotation. If you are using the same ring and pinion and case then it's not too much of an issue. BUT, if you are converting to a "Freeway Flier" R&P and flipping the ring gear (as I am attempting) then you need special VW tools (rare as hen's teeth) or LOTS OF TIME to assemble, fit, measure, disassemble, shim, reassemble, fit, remeasure, etc. until you get the proper gear mesh on the R&P. That's where I'm at for now. The disassembly of the gear stacks and syncros is pretty straight forward like any standard rebuild. You will have to either get some VW fixtures or have a junk trans housing to cut up to provide a jig for the reassembly of of the gear stacks and adjustments of the shifter rods.
Expect to find worn out syncros, goobered up gears and worn or broken shift forks on any used (Not recently professionally rebuilt) trans. Tracking down the correct parts can take on a life of its own as not all VW parts are created equal and the variances can mess you up.
https://thesamba.com is a good resource for information and parts.
I presently have the gear stacks reassembled and the shift forks adjusted. I recently located a guy from my VW past in Memphis who used to rebuild VW transaxles and he has agreed to help me with the R&P adjustments. Hope to be able to set aside some time soon to tackle the R&P.
Another major hurdle for my project is that I want a foot shift, hand clutch setup. I really can't proceed on the clutch actuation geometry design until the trans is together and functional.
Luis' product is first class and professional in it's fit and finish. My transaction was easy and straight forward. Almost as easy as buying off Amazon. I used PayPal as they could handle the currency exchange rate and set up an escrow account to hold the funds until the product was delivered. We used DHL because they gave the best shipping rates and handled all the export/import paperwork. The shifter was delivered in 5-6 days from being shipped. Pretty good for Brazil to Arkansas!!
The sequential shifter is a bit pricey due to limited production (built to order) and higher shipping costs but if you don't want to be tied to an H pattern shifter or want a foot shift setup this is probably your best bet.
Good luck on your build.