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Yes I have used the Techlusion 3.5 units. They are OK.
They are still a piggyback unit that intercepts the injector on-time and allows you adjust it in various ways. They just do so manually - without a software interface required.
Mark Dobeck started Dynojet (three owners ago - when the V-Max first came out), and his first units were some of the very first units used to adjust fuel injected bikes. We jumped on these quickly, and they worked pretty well on those first EFI engines. The newest versions have come a long way. He also makes units for other companies like Vance & Hines, Two Bros., etc.
The two guys that originally did the electronic and software work for Mark Dobeck, went on to work for Marc Salvisburg at Factory Pro on his early TEKA 2 units. The TEKA 4 units are similar to other piggy-back units, with a bit more resolution at low throttle positions.
Bazzaz also makes a piggy-back unit, as well. Some prefer these to Power Commanders. I find the software a bit clunky - especially if you turn the bike off and leave the software running.
Microtec makes a few different piggy-back units too - as well as aftermarket ECUs.
I can make a long list of other units I have used over the years, as well as some new ones that have come on the market in the last couple of years.
Today, I am not a fan of piggy-back units - especially if you have the option to tune directly in the ECU. If there is no other option, then I use them. But they are 20 year old technology with slightly more memory and faster chip speeds, and the industry is changing...
finally.
On many of todays bike engines, we are seeing a transition to using multiple injectors on each cylinder - this is a good thing. However, you need two piggy-back units to control these different sets of injectors. Some injector sets are staged to come in at higher rpm, some OEMs transition from lower injectors to higher injectors at higher rpm. These different injection strategies require different tuning strategies. Some that is not well done with piggy-back units.
In some cases, you can install a unit on a bike, and they alter the fueling slightly - even with completely zeroed settings. This is just a side-effect of them being in place and intercepting the injector signal. Then there are times when they don't always work as they should. Most units only last 3-5 years before they start having issues. I have seen them last longer, and I have seen them not work right out of the box.
As you modify engines further from stock, these piggy-back units become less and less able to cope with the required changes. For this reason, many racers use OEM or aftermarket race ECUs. And we are finally seeing more and more interface software for the stock ECUs. This benefits racer and street riders alike.
In my opinion, you are much better served with software interfacing directly with the ECU that allows you to alter many things that are not controlled with a piggy-back unit. The hard part, is finding someone that will tune the bike with anything other than a piggy-back controller - the software is less simple, and not alway easy to learn what does what. But it is not hard either.
The major motorcycle dyno company has a death grip on the motorcycle tuning market selling piggy-back units. They are not about to get behind anything that cuts into their bottom line. As a result, dyno owners and operators are on their own learning to use other tuning solutions. A few of us have been racing down this road for a long time. We do what we can to help the rest get up to speed - to no benefit of our own. Likely a stupid thing to do.