spring for l96?

Im fairly new to airsoft and im looking to buy a new spring for my l96 and i have no idea what the numbers like 130 or 190 mean, but what spring do i want if i want my fps to be 500 or a little more.

thank you

Many other upgrades have to be done to put a powerful spring into a sniper. By powerful I mean m150 or over. It has been discussed many times. If you pm sniper 004 he will list every needed part, as he has perfomed close to every upgrade. He would give you a list, and an accurate price range, and Also, Airsoft Atlanta is the way to go for sniper upgrades.

ya im aware that other internal upgrades are required but i just wanna know which spring would give me 500-510 fps? or do u mean that there are other upgrades that could increase fps other than a new spring?