When I looked into the plug-in world back in 2016, the Sport Tune was a new product, and, as has been discussed, did not come with the more comprehensive Dinan warranty.Since all these piggybacks are emission illegal and no warranty, is $250 Dinan Sport a viable option within the group?
I felt that adding 3 psi of extra boost, coming on early in the rev range, with all other parameters controlled by the factory engine management systems, seemed a safe enough bet. I had several conversations with tech folks at Dinan, who were in California then and were fonts of information and very accessible. Not sure that's still the case regarding information and access.
I've never unhooked the box when I've taken the car in for service, and never had an issue with engine performance. BMW/MINI techs have seen my installation and their only comment was they wanted to drive the car. They seemed well-pleased with the extra grunt they experienced.
The plug-in, which is the most basic/crudest enhancement approach, can create momentary over-lean conditions. But the engine management computers are so fast now and the fueling and air adjustments are almost instantaneous, so there is almost no risk of damage or a code if one doesn't go higher than the Sport+/3 extra psi level.
The more sophisticated boxes and tunes mess with several parameters and hook into more engine sensors or adjust parameters from the various sensors. Many claim the more sophisticated tunes are smoother and offer more bang than the simple plug-in boost-tricking single sensor boxes. I'm sure that's true.
The new generation of BMW engines are amazing machines, and the factory auto tranny algorithms are truly amazing in most situations. My 2020 is more refined than was my 2017 version of essentially the same drivetrain. Overall, the cars continue to improve.
When people ask me how I like my plug-in, I tell them I like it, it's been trouble-free in 2 cars, but I always end with clearly stating that I am assuming all the risk for a little more fun.