Considering the cams you are running at the moment, either setup will be a vast improvement. Being that you aren't running a huge turbo, the power difference of the 264 inlet cam over the 254, i wouldnt expect to see an extra 20rwkw between the two. Its all up to you, but considering you are almost at the limit of streetable 2wd power, i would go the smaller inlet, to maintain the low rpm torque, and idle quality, but its all trial and error.