The stock wheels will not clear without spacers. I have the stock 7 spoke alloy wheels with 26mm Z32 brakes and the wheel would barely nick the caliper. I went to
http://www.enjukuracing.com and bought 5mm spacers. Problem solved.
I'm sure if you were to buy 5mm spacers for the steel wheels that they would clear aswell, don't quote me on this though.
Oh, and about redrilling them for 4 lug. If you have access to a drill press, simply placed the stock 4 lug rotor below the new Z32 rotor and use it as a pattern. Start off by aligning one of the holes. After drilling each hole I put a bolt hat fit snuggly through each one to ensure that nothing moved around. Of course, your going to want to line up both of them perfectly and use clamps to keep everything in place anyway.