I had to decide when i got my 155 bow front whether or not it was worth it to drill. Drillin of course looks better but are you willing to risk losing your 300+dollar tank if it cracks? Remeber....they dont garauntee that it won't.
I decided it wasn't worth it and went with an overflow which works great. BUT... nowadays they have a built-in overflow/prefilter with built in U-Tubes...AWSOME...you can barely see it and it's quiet too...you can prob pick 1 up for about $100 and fit it into whatever size bio filter box and sump. Im thinking of getting one right now even tho my prefilter works fine....its just an ingenius idea that make your tank look so much better.
good luck