Load resistors aren't needed on the brake bulb, just the turn circuit. A single pair of 3 ohm 50w load resistors on the turn circuit will do the trick.
There are two types of LED bulbs - standard and CK, the difference being which pins are power and ground. On my 06, the front turn/park 3757 are standard... for the rear, brake is CK, turn and reverse are standard, all 3157.
Putting a CK bulb in a standard socket will not allow it to function correctly and vice versa. A side effect could be a blown fuse clear up to melting the socket or worse. This video will help determine which socket style you need to buy bulbs. Check your front socket before ordering those. GM used CK up front for a short time. For the most part, the rear hasn't changed from ck brake/standard turn/standard reverse.
[video=youtube;V8ONj-NJdjA]http://www.youtube.com/watch?v=V8ONj-NJdjA[/video]
One last caveat: if you get 3157 bulbs for the front due to not being able to find 3757, you may need to shave off the little nubs on the side of the base (circled in red below). 3157 has a wider nub that 3757, other than that they will interchange.
Hth