Get the techt l7 bolt over the firebolt, it's better. As far as asa I'm looking at the dangerous power ones with the lever. I can't remember the exact name but they seem to be very nice. Barrels are kinda personal preference, if You have the cash get a freak kit or similar kit I'm sure there are others.
you can also change the hp red, im pretty sure the warranty will not get voided unless you drill, mill, anodize, paint the body, or do something crazy to the gun.
If something does happen just put the stock parts back on again.