It really depends on you. What I mean by that is if you feel comfortable taking your gun apart, polishing surfaces, and replacing parts then I would go for the tune up option. If you prefer a turn key product that doesn't need much work done, but you're willing to pay a premium for then go the xtreme route.
For my stock 2 I chose to tune it up and I am really satisfied with the result, it saved me a lot of money and I got to put exactly what I wanted into the gun. I also personally think that the non extreme versions look better than the xtreme versions, but to each their own.
Either way you won't be disappointed, good luck!
