Drilling your rims is probably on of the greatest risks you can take with your wheels, unless you have wide, undrilled rims I wouldn't recommend it. If, however, you do drill your rims only drill small holes evenly spaced between the spokes. On the subject of rim grinds, any rim can be ground as long as it accepts a rim brake. If you decide to grind your rim you'll also need to upgrade your brake pads, personally I use TNN LGM's and heatsink blue's. It's all personal preference and you will work out what feels best for you in time