It definitely does not have the impact the good DynoJet tunes I have in my Indians. But it does offer subtle improvements in fueling that smoothed out the off idle and midrange rpms.
Wether it’s worth the price of admission is your call.
The reason they use mineral oil is that unlike brake fluid it is not hygroscopic so it shouldn’t need to be flushed regularly like brake fluid.
I had to replace the fluids when I swapped my handlebars and lines. I can confirm the BMW clutch fluid is blue mineral oil.
I watched that video and I can tell you mine are attached much more securely than what he shows. I attempted using the same nylon pry tool and they didn’t budge.
You can leave the catalyst and flapper (fin?) by leaving the headpipes intact. The mufflers are a simple removal and you can modify or replace them without any emissions concerns.