[Harrison]

You could always drill holes in your motors (maybe the battery and pnumatics as well...lol) j/k

Seriously tho, NEVER USE STEELE (unless you have no choice, in which case pump it full of holes). Aluminium is great, in some cases you can even get away with plastics (altho is this risky in gearboxes).

As for holes in general, unless its steele, it won't save much weight/hole (maybe only a gram or 2). But, with A LOT of holes, those grams to slowly add up. And when it comes down to the wire for weighing your bot, those grams come into play. When it came time to weighing our bot last year, we were 130.1....take off a screw, and we were 130.0. Every little piece of weight you can save, save.