[MiloXC3]

I use a full length paper barrel spacer.

Yes, they are definitely worth it because they will improve your consistency in accuraccy, but there are cheaper alternatives. The was barrel spacer is a good one but I've never tried it myself!

 

[MiloXC3]

I use EzShape non-hardening clay for my stock.

 

[MiloXC3]

http://www.airsoftsniperforum.com/showthread.php?t=4068 is the best I can find.