The reason a lot of clones shoot high is because the Chinese manufacturers have caught onto the fact that a lot of newbs equate FPS with better range and accuracy. There are 3 things that will influence an airsoft gun's range accuracy far, far more than FPS:
1) Weight of round. 0.20's are usless for outdoor. They bounce off everything and don't stabalise well. Heavier rounds may not physically fly as far, but they'll be stable for more of their flight, actually giving you a longer accurate range. Most people use .25's and .28's. CDN_Stalker did an awesome study on BB weight and accuracy last year. It's sitting in the forum here somewhere, do a search for it and have a read.
2) Tightbore: Helps stabalise the BB on a narrow flight path before it even leaves the gun.
3) Proper hop-up adjustment and good hop-up. A really good hop-up will also do far more for your range than FPS>
4) A well built gun. I know I said 3 things, but this deserves to be mentioned. This is another bonus of buying more expensive guns over a clone. Just ask Crunchmeister about his Real Sword AK shooting 330 and how accurate it is.
The "sweet spot" for BB's is usually around 360-380 (chronied on .20), shooting .25 or .28 rounds, with a good and properly adjusted hop-up.
"Someone in a Prius tried to race me at a stop sign the other day. I couldn't believe it. I had him for the first 100 feet or so but I can only walk so fast."