MrPlumber,

You can be the guinea pig and open the pandora box of free tuning.

Anyway all freeware tools pose significant risk, since they come with no warranties.
I will even doubt the xdfs, the wireless flash tool and even commercial tools can have errors and brick your pcm with absolutely no money back.

To give you a piece of mind. When the checksums are good the pcm can reflashed.

Just start with junkyard spare pcm and start experimenting.