Ali SC3

iTrader: (10)

just used a step bit in the middle with a can of grease.
cover the bit with grease entirely (just stick it in the grease completely)
drill a little bit at a time until you see a lot of shavings,
remove and wipe off bit with cloth, then repeat.
as soon as you break through, back it out, clean it off, use a lot of grease, and drill the rest of the whole. then use your finger with some grease to make sure its 100% clean.

I flushed out the oil right after and I didnt even have any shavings in the pan.
Just make sure to take your time and it will save you alot of time later.
covering the bit in grease each time you drill made sure all of the shavings stick to the bit, instead of having to dig em out later.

oh and for the 2 side bolts, I never even drilled out the holes, they are already drilled out enough. I just used the closest fitting tap I had, and went and bought bolts from the store. worked just fine for me.