Type 96 or Sr-2

You might want to steer away from the SR-2 because it has a fixed hopup. I'm pretty sure PDI just came out with an adjustable one though so if you do choose the SR-2 all hope isn't lost. The SR-2 was designed for close-range target competitions in Japan so I don't think it would hold up for too long in a rigorous milsim environment.

The Type96 would be a better tactical rifle mainly because they just shoot beautifully. They have larger cylinder displacement than most APS's so you can get a super long barrel and still have quite enough air to send your bb downrange with some umph.

Out of the two I'd definitely say get the Type96 because of it's tried and true accuracy and dependability. The SR-2 hasn't been around enough for 1) people to have used them extensively in actual airsoft games and 2) parts to be readily available.

EDIT: Dutton posted while I was typing, but you get the idea.

Maruzen just released the LR (Long Range) version but it still would be unwise to choose it over the type96; Stick with your decision.

Just letting you know it's out there and supposedly comes with an adjustable hopup out of the box:
http://redwolfairsoft.com/redwolf/airsoft/ProductDetail?prodID=25914

Good choice, Laylax is the way to go. My M24 is all laylax'ed out, it will be completely done when I get my zero trigger in a couple weeks.

The PDI vacuum piston, if you're still curious, isn't all that great. The integrated pistonhead is loud and with high velocity springs it shows signs of stress and compression early in it's life. I like the idea they were going for, but the pistonhead just could've been designed better. I suggest the Laylax 3-element piston for your 96, it's an amazing piston(pink, too!)

http://www.uncompany.com/pageproductdetails.asp?prodid=1053