Well, for starters the hop-up isn't the greatest. Works great for a bit, then drifts down to be needing a replacement. Mine broke on me and I had to get a replacement (though, I got the regular and not the alluminum).
These two parts should solve almost all the problems I came into contact with:
http://www.evike.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=W&Product_Code=Parts_BG_98K_01&Category_Code=
http://www.evike.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=W&Product_Code=Parts_BG_T05&Category_Code=
With those, you should have basically the grim reaper in your hands. Had I known of the Nozzle kit, I would of kept my M700. The thing may think it hits high fps, but when it actually hits, there's almost absolutely no feel to it. I don't know if you remember the game out in Romulus when I brought it and it was the M700s + spotters vs. everyone else, but everyone saw it chronoed well above 500, yet when I shot a teammate within 20 feet, he didn't feel it hardly at all. With that high of FPS, you would think it would hurt like hell. I was running .29s with it. You may need to run aluminums in it, as regular BBs just don't transfer the energy that propelled it out, so to speak.
You can get away with running it stock for a while, but, I would get those upgrades, plus, since fall on us, and almost winter, I would put this project off to the side for a bit.
Also, not needed, but a good option since you may be taking apart it if you get it, is the G&G Power Bolt. This eliminates fluxuations the gun sometimes does on it's own. It's cool to be able to adjust the power of the gun, but, mine broke on me and was just a real pain in the ass. This way, you will always know what fps area you are shooting.