Don't mill the head because if it needs rebuilt ever you will be buying another head if it's out of tolerance. Should of went with oversized valves. Use stock cam gears for what you're doing. With a stock bottom end you might gain around 20-25hp with what you have depending how good your head flows maybe a little more. With the stock injectors you can just use the stock ecu unless you have big plans down the road get megasquirt. An underdrive pulley would help too. Egr delete, bore the throttle body or get a 60mm tb, header exhaust ect.

Jj