Going to a rope backstay from wire is a common practice to reduce weight. You are right that it is illegal under class rules. But under PHRF, you should NOT recieve a penalty. I say should because, being a PHRF handicapper myself, I know that our region does not penalize a change like that. But I also know that not all regions are the same. Check with your handicapper first.
If you want to reduce weight aloft, I suggest that you copy the J24 fleet. Get rid of the luff track on the forestay in favor hanked on headsails. Get rid of one jib halyard (how often do you really change sails anyway?). Get all the lights off the mast. Move your antennae to the stern pulpit from the masthead. Convert to stripped-core halyards for the main, spinnaker and jib. If you really want to get picky, you can strip the paint off your mast and have it anodized. All that should be left is a bare mast with 3 halyards and a windex. You might even consider going to smaller shrouds from the oversized ones that J30s were made with.
Have fun....
[This message has been edited by Alan Grim (edited 12-29-2001).]