I've been avoiding getting involved with this thread because I'm both an ITR driver and also on the ITAC, and I don't want my personal opinion construed as "the plan of the ITAC." It isn't.
But I think Kirk has it totally right. I think there aren't that many ITR cars and it's not that big a deal for those who have removed it, to add it back if they want to. We have to do it someday, so why not now? In the interest of full disclosure though, I did a brand new build in winter '06/'07, and I chose to keep the ABS hardware in the car just in case this rule ever changed. I think it's a performance advantage and I'd use it if I could.
Now ... I really hate the idea of "pick which rules you want to follow, and that will determine your weight." As in, one ITR BMW 325i might have a minimum weight of 2765, and that other one that looks just like it might have a minimum of 2965. I hate it. One weight per make/model/year/engine please!
I don't think there's an ITR car for which the factory ABS would not be an advantage, therefore, I'd give weight breaks to the *3* (now 6, with those old 911s we added) cars listed that never had any ABS available, as part of the weight-assignment process (it would be a subtractor if there was no ABS available). For cars that had it available but for which the driver thinks it's not an improvement, well, go ahead and remove it, it would still be allowable. For the people that did a new build and tossed the parts, well, nothing would be forcing them to go put it back before their next race, but if they felt it would be an advantage, sure, they would want to go back and re-acquire those parts sooner rather than later. I see the inconvenience, but for the good of the class & category, this would be my vote.
However, we put this out for member input, and got very little. But with one exception, every letter we got was from someone in that last category, who didn't want to be inconvenienced like that. The other letter was from someone without an ITR car but who felt that it was a bad step down a slippery slope. Add that to the original letter requesting the change, and we have exactly one member writing in requesting the change. That's not enough positive feedback to support a change, as, as Kirk pointed out, the status quo wins without compelling arguments and support.