mines flatbellied but i dont dd it...you will definetly have more vibrations if your solid mounting your crossmember to the frame...ever since i did mine ive had interesting noises coming from the tranny and t-cases. i added a little more gear oil to the tranny and t-cases and it seemed to help a little. im not sure if its an oiling issue or what?? im also not running cv's at all front or rear so those might help with the vibs too. im not sure if i would go completly flat with the frame if your dd it, and if you dont want to lift your motor mounts.
let me tell you it will help out if you do a lot of rock crawling
