Solo,
The reason most everyone keeps the stock cross member even when ditching the old I6 is for the body mount that is built into it.
If you subframe your truck, you will lose the body mount and will have to make a new one. I found that it is very difficult to do this properly and make it strong enough to hold the nose up.

Now my truck has a saggy face! Needless to say I will never ever subframe another truck. I don't care if the parts do come in my favorite variety, free!
Sorry, I got a little carried away. Hope this answered your question. Anything else, feel free to pick my brain. I have probably made that mistake already! :rolleyes: