I just started putting together my sniper rifle as well, and it definitely is an investment.
I started with the UTG L96 Shadow Ops like you mentioned
http://www.amazon.com/gp/product/B000O0O296/ref=oss_productI added a Leapers 3-9x40 Illuminated Mil-Dot scope
http://www.amazon.com/gp/product/B001BR6RCG/ref=oss_product with a UTG 1" Medium Profile Mount
http://www.amazon.com/gp/product/B002TUSJT8/ref=oss_productThis is as far as I have gotten, and I am waiting on the rest of my upgrades arrive. It currently shoots 420-425fps with .30g bb's (didn't have any .20g's to baseline.)
I just ordered the following from Evike and I will post the results once complete:
- UTG Shadow Ops Sniper Rifle Upgrade Kit
http://www.airsoftpost.com/product_info.php?cPath=24_611_612&products_id=32451- EdGI 6.01mm TBB (499mm length). This particular TBB is made for use with the stock hop up. EdGI also makes the same barrel for the PDI hop up, so be careful when ordering. A PDI hop up is a worthwhile investment if you can find one. Tokyo Model Company out of Hong Kong is the only site where I could find them instock, but I didn't want to mess with overseas shipping and customs.
http://www.airsoftpost.com/product_info.php?products_id=31872- PolarStar Barrel Spacers to hold the inner barrel tightly in place
http://www.airsoftpost.com/product_info.php?products_id=32469As soon as these parts arrive and I get them installed, I will post a follow up with the new chrono results. I will chrono it before and after with .20g's when they arrive as well.
Depending on the results, I may add an upgraded spring and a Laylax Zero Trigger as well. The stock trigger is plastic, so if you put too much pressure on it with an upgraded spring it will break. The Laylax is metal and will allow you to put any spring you want. It'll run you $200+ though, so it's definitely not a cheap addition.
The nice thing about spring guns is they are very easy to work on yourself. I have no idea if the investment is going to be worth it in the long run, but at the very least it is a fun project.