I put the Dobeck AFR+ on mine, and it works well for what I was willing to spend and ease of use. In my opinion, if you aren't going closed loop at cruise or setting to an AFR under load, you're missing out on power and can do damage since you literally are going "seat of the pants" unless you're using a wideband and watching it. The Dobeck AFR and the PCV are the only ones that do that. The Power Commander is for folks that want to tinker, and the Dobeck is for folks that want to set an AFR and just ride the heck out of the machine. One warning though, the air injection needs to be blocked off, or the AFR will hunt until the cat lights off (function in the ECU that turns the valve on and off when cold).
Bang and smiles for the buck, I'd do the suspension and tires first. Turns it into a machine you can trust at high speeds in the dirt versus something that is trying to buck you off in the woops. Having real rebound control over the rear end is a must. Pick the tires that best suit your terrain and level of road/trail use and have the suspension set up for your intended use. Travis at Go-Race knows what he's doing, and there are others. My 2015 rear shock had the same issues that they've had since 2008, and he fixed them. It's worth it, just do it. You don't need 2HP if you can't plant it.
Been riding for a long time also, and feel the same way Fiftygrit does about that. Don't want to date myself, but I had a brand new 1977 DT100 early in my riding experience. And it wasn't the first bike. Ouch.