i shoot 501 grain easton xx78 super slam slect ultra light arrows not exactly light i get 258 fps to me i like it but what kinda lighter carbon arrow would you guys prefur possibly around350grains..[X(]

Well, you obviously don't like what you've got very much or you wouldn't be wanting to do something different. If you want to try carbon, then get some GoldTip XT's and don't worry about trying to get down to 350 grains. You'll gain plenty of arrow speed. Even at 400 grains, you'd still be clocking along close to 290 fps, depending of course on how efficient your bow will be with lighter arrows.

i would shoot the gold tip like arthur said because i have never had a problem shooting them

Golt Tip XT's Ditto

What draw weight and draw length are you shooting? Going down to 350 grains may do more harm than good. As Arthur made reference to, I would take a look at some of the more reliable ICS style carbons on the market and make sure you have the proper size for your setup. Total arrow weight, in many cases, will fall right in line provided you don't go with one of the lighter (Grains per inch) styles.

258 is plenty of speed, unless you are ate up with going super fast. Does your bow shoot good now? Is it quiet? More than likely 350 would be way to light anyhow as was said.

IMO, you already have a great arrow...280 or 290 doesn't kill them any deader than 258. I would shoot ACC's if I was considering a change to a smaller lighter arrow. My .02

You are already kicking a 500 grainer at 258, that's a lot of speed for an arrow that heavy. I wouldn't go down under 400, your bow will be a bit quieter if you keep a modest arrow weight. GT XT's are a good arrow. Personally I wouldn't change.