I did a lot of research before getting a SmJr. I had a powerMax PCMR or what ever it's called and it constantly threw codes. Finally ripped that expensive thing out and tossed it in the trash.
Since the Smarty has no hardware to connect, it doesn't junk up connections and have wires hanging all over the eng. It also maintains max. pressure levels set forth by Bosch so there is no unusual stress on the FI system. I've been pulling with it on the 100HP setting for several years and don't plan on changing. If there's a down side to this programmer, I haven't found it. Fuel efficiency didn't change even with the added power. No or very little extra smoke.
You will need to do some upgrades on your auto before using anything above the 30HP setting. I wold also at least install a pyro gauge.