New M4 Front Blocks

[MHeadling]

Iv just got the new M4 front blocks, part no U3556 to fit on the Cat

I have bought a M4 tap, now my question is:

Can I be lazy and whip out the diff and drill and tap the bulk heads on the car?

Or is it better to take the bulk heads out and drill them on my pillar drill?

With me feeling lazy, I like the look of option one but I don't want to cock it up as te Petit isn't far away now!!

Opinions please!