Marui M90 upgrade...?

Can someone tell me what parts I need to (lightly) upgrade a Marui Ver 6 to a M90 spring? My local limit is 0.95 joules (95 M/S, or 311 FPS).

how about an tight bore barrel and hop up

Is that enough? What hop-up bucking gives the best range and FPS?

(for the record, anything over .989j is illegal)

those are the easiest of upgrades, pick up some FPS that way, especially since your in Japan, your options are limited! swapping out the spring is really not an option at this time, I believe it's firefly that you want to buy, a course not sure if the local shops will carry such, the barrels would any tight barrel , you may even use an silcencer so you may gain more accurancy that way also, without cutting the inner barrel down so much. the experts will review this which is CDR, Allout, and few others.

Is there a reason I can't put an M90 in? You're still allowed to upgrade, just can't go past 311 FPS due to field/team regs.

It's only marginally stronger than the stock (M85, IIRC) spring, but what do I need besides a spring and spring guide? I may or may not want to bump up to a 9.6 for a higher ROF, but dont want to strip the gears or piston.

I think a 'silenced' piston head would be a good idea since the stock P90 is so loud.

I may be getting a cheap Chinese silencer whenever I order some mid-caps from Hong Kong. But I don't think I'll be going with an extended inner since I like the compactness and easy handling.

With the inner barrel your only going to make it as long as your silcencer., with the M90 spring it hit or miss to get on your mark of 311 FPS

Howie wrote:With the inner barrel your only going to make it as long as your silcencer., with the M90 spring it hit or miss to get on your mark of 311 FPS

No, I mean I would probably take the silencer off as much as I put it on. I would be willing to get a barrel that goes as far as the flash hider though (maybe 20mm longer).

I thought an M90 would generally put me around the 300 FPS range?