The rifle, with a retrofit with a "bullet button" magazine lock and replacement of the flash hider with a muzzle brake would be California legal.
Costs expectations at retail seem to be in the range of circa $1500 dollars, wholesaler prices circa $1100-$1200.
Browningguy, love to know where you can get AR10''s at $1000, they're north of $1500, same with FS2000, at $2000 and above, assuming you can get your hands on one. You MIGHT be able to get a DPMS Panther LR-308 AP4 for about $1300.
In addition that rifle would be a minimum of 8" longer with a 2" shorter barrel and still DI not piston.
Don't expect 6.5 or 6.8 anytime soon, the immediate push is to get as many of the 18" "Carbine" version in 7.62x51 out as possible.