What holes were you needing to drill besides the ones that hold the heat sink in? You CAN get three wires, a power pair and two cat 5 through the grommet in that plastic box into the light area. It may bulge that grommet a bit and I took a pair or needle nose pliers to that bulge to get a bit more room for stuffing wires, but they make it.
Also HF had the lights on sale for like $10.20 and then I brought my 20% off coupon as well.