PDI have been good to me, but personally, I went the laylax route for simplicity and I prefer their piston design with the accuracy cup over anything PDI uses.
Angel custom is kind of like the clone of laylax and has decent parts, such as spring guide, and piston, and are good for on a budget. I would stay away from their springs though. For some reason, my SP150 ran around 480 fps to start and just kept on dropping over the next few hundred shots wayyy below the fps output on my laylax sp150.
As for hop up, go with the HP chamber. The PDI chamber, I found to be lacking and a pain in the ass. The HP chamber is like a improved stock chamber and uses AEG barrels and buckings and also is more consistent and better sealed/easy to work with. More user friendly than the PDI chamber.
Last Edit: Jul 9, 2012 16:20:53 GMT -5 by fuzzywolly
I would like to comment that saying "sniper" when you mean "sniper rifle" is steadily approaching being a warnable/bannable offense here. If you're thinking of getting a brand, I'd go with a tattoo instead. They hurt less and look better. If you want to talk about brand names of parts for sniper rifles, say so.
GK Backup Jacko
"Zorak's like a Long Island Ice Tea of hate." -Xaos