Either is good and both have their own merits but if I were you I'd go with the M4. ICS is definitely nice with the split gearbox design but it also takes proprietary parts like other posters have said. That said, I believe there are some parts that are common to the "traditional" TM based gearbox design but I would say probably less than 80% cross compatible (although some people have said there are 3 main parts that are proprietary and you must get from ICS).
Just go with the traditional tried and true design so that you can gut parts from other parts guns and such and you have something "reliable". Then when you feel ready to take it on get something else. (ie. Start off with an AEG, then maybe transition to a GBB or GBBR keeping the AEG in your trunk at games in case your GBBR goes down or in case someone needs a rental gun or something).
Also all you need is ID proving you're 18+ the AV system is only internal to this site and has no legal bearing whatsoever. We've just chosen to implement this system as one of those precautionary things. Outside of the site we can't control and only in Ontario is it law that you must be 18+ for airgun purchase (includes paintball, BB, pellet, airsoft, etc.). Other retailers (ie. Canadian Tire) may have a blanket 18+ policy across the country even though they're not legally obliged to elsewhere.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE