Josh,
Seem like an ok idea, However on the way to work this morning I was think about how to define this in the rules and how to prevent some one from taking advantage of it. IE making some non standard cross member with the intent to gain some advantage rather than just making the car more serviceable.

For example. a 3piece crossmember could lower the engine a little bit in an effort to lower the CG. Sure the ones that are out now don't do that, but.... it something we need to address in the rules.

Given that it maybe something we put in the 2011 rules so we have time to construct the proper wording.

Joe, at least the ones I've seen are built from factory crossmembers that are sectioned and fitted with splice plates. All the original mounting points stay, and the geometry of the crossmember remains as factory. It seems easy to confirm with visual inspection. A fabbed peice would be hard to control.

I have the Lindsey 3 piece crossmember in my car - was an item I wanted to do in order to make it easier to maintain. I see no performance advantage out of it b/c it simply replaces the stock crossmember and does not change the geometry of the car. It does create another stress / bend point in the car so it may actually slightly impede performance (I have no proof of such).

Didn't Porsche for the Firehawk 944 cars they build have custom fabb'd removeable crossmember for easier access to the oil pan?

on Saturday one of the rmr cars had a 3 piece X member fail ... he was racing in a enduro 30 minutes into it .

Wow, good to know. Where did it fail?

I've heard of homemade / custom made ones fail.