[Hectic]

I personally am not a fan of the pdi hop unit. You have to remove the mag to adjust it and the set screws can loosen off damaging the nozzle or at the least just not holding the setting. Perhaps some loctite after you set it but that still isn't verry useful in the field for adjusting on the fly.
I'd go laylax myself but then I don't know how the pdi nozzle will go with the laylax hop up. Altho i know the pdi v2 works with most nozzles.
Also why so long, if you keep the barrel 455 or shorter you won't need to bore up unless you wanna run bb's above a .40g (prety useless around here, not enough safe range)
Edit. The edgi barrels are nice but you can get quality barrels for less and locally. All the normal brands come to mind really. Depends if you wanna drop 60 buck or 150 lol
Using a laylax hop up you can grab any aeg barrel you like.
I personally run 455 mm madbull 6.03 or 6.01 depending what was available. Currently a 6.01.