depends what you wanna do with the truck.
IMO- If you are going to get twins get something that matches up with another charger, save money. As far as twins go... generally you don't need the bottle.
If you get a stout twin set up... you'll need everything else to enjoy it. Rods, pistons, $$$$. If you "cheap it" or cut a corner it'll haunt you, sooner or later. Unless of course you only drive it occasionally on the street and usually at the track. That buys you some time.
Lots of opinions on which charger is best for what application. The bigger the charger the bigger the sacrifice in some area of performance... Hits so hard it blows the tires out, sluggish bottom end... tough to tow below 2400 RPM etc etc. Don't forget your Wife may wanna drive it someday to... keep the truck straight and her and the kids alive (Witches excluded).
Good luck!
I think N2O and a smaller charger with DSP 5 would be best for a DD/hot rod set up, throttle response, drivability, and air in a bottle (N2O) for the track.