http://polarstar.tklapp.com/products/precision-rifle/vsr-10-series.html It appears that you can buy directly from PolarStar's own site. Never came across it before today. Two components I find intriguing are: $35 Polar Star High Flow Cylinder Head $65 Polar Star 90 Degree Piston Shipping is $5. I have the stock teflon sealed cylinder head and piston that comes with the AA Zero trigger, which is doing a decent job at air seal, but not the best. Are these two components worth the $105, or is there a better cost-effective deal? From what I've heard, I expect that PolarStar provides THE highest quality VSR upgrade parts.