It controls the wastegate, allowing to remain closed until it reaches a boost level adjusted by you with a threaded shaft/nut. It replaces the vacuum controlled unit and allows the boost level to run higher than factory setting. I'm not familiar with a 2000 setup but I believe you'd still need a boost fooler to prevent the ecm from responding to the perceived overboost by defueling...unless you chip it.
I went with a TM as I'd already blocked the EGR and boost was the sole remaining use for vacuum. I then removed the vacuum pump and realized a small increase in fuel mileage.
Discussing the merits of additional boost without a chip upgrade is like broaching the "best" oil topic on a Harley site. I'm happy with mine just for the simplicity...one less complex thing to fail.
If you want more, just use the "search" tool and type "turbo master". Make sure you have a few hours to spare, though, there's a lot of good reading to be had! :smile5: