If you want check out my link to my thread. Towards the bottom of the page there is a four part upgrade process. It includes the order of what to upgrade first and last. However, it applies to specific parts for the l96, make sure you get the parts for the vsr. But overall, it is the same concept. With that said, do not upgrade the spring until all the necessary upgrades are purchased first. Link:
http://www.airsoftsniperforum.com/phpBB/phpBB3/viewtopic.php?t=1156
Brief summary for the vsr-10 upgrade process
First upgrade purchase
-Aero Chamber
-Aeg bucking
-Aeg tightbore barrel
-Homemade barrel spaces (electric tape wrapped around the barrel to desired length)
-heavy weight bbs (I love madbulls) Note: do not use cheap bbs; you will only regret it
Second Upgrade Purchases
- Cylinder head
-spring guide
-Piston and piston head
-Cylinder (optional)
-Optional: Piston sear/trigger sear/spring guide stopper
note: at this point, an upgraded spring is optional
Third Upgrade purchases
-Cylinder (if not yet purchased)
-Zero trigger (optional and only needed if sears were not purchased)
-Spring upgrade
Fourth Upgrade Purchases (externals) Not all necessary, but looks good

-bolt handle
-flash hider/supressor
-flash hider adapter
Other recommendations: Clean your bbs
Here is how:
http://www.airsoftsniperforum.com/phpBB/phpBB3/viewtopic.php?t=1037
Do it yourself mods are good. Type "vsr-10 do it yourself mods" on google. There will be a ton of information for you.