Sorry you posted back up before I could do and edit of my last post.
Ok since I only plan on running 33's on my rig and going no bigger due to having to regear and all that fun stuff. Having a 2.5 kit already installed I can do 3/4 spacers and still be ok with the addition of a BL and MML and extra hardware such as a TC bracket ECT. So I don't rub under full flex. Now that would give me 4.5 inches of lift for tire clearance not 4.5 inches of true lift that I would get from a full out kit. This also keeps me from that border line of having to install the SYE and DC. Correct? Or would it just be better to do the BL and MML and not worry about any further lift in the suspension. My understanding with the BL is if you don't do the MML then you have to trim the fan shroud.
Ok tire rub has nothing to do with transfer case/SYE or lift height. Thats an entirely different subject.
With a 2.5" lift and a 2-2.5" Tummy Tuck (high clearance transfer case skid plate), you are right on the border of needing a Double Cardan Shaft - thats 4-5" total lift. I have a 1" BL, 1" MML, 2.5" OME lift and a 2.25" TT - I had slight vibrations from the driveline, so I installed a 1" transfer case drop. This pointed the output shaft toward the axle enough to eliminate the vibes. All this is in My Build Thread, linked in my sig - yes, I have a TT with a t-case drop. I've seen this same lift on a Rubicon LJ, one which had slight vibrations from the drivetrain - the double cardan shaft was required.
Rule of thumb:
Total Lift Seen by T-case = Suspension lift + Skid Plate Lift
Skid plate Lift = distance output shaft moves up from stock location (usually same as advertised clearance increase)
Body Lift doesn't count - it only makes clearance for moving the drivetrain up with a TT.
When you install a High Clearance t-case skid, called a Tummy Tuck AND you install a MML, you are basically retaining a close to stock driveline angle
from the crackshaft to the output shaft. This doesn't mean you can subtract 1" of lift from the above equation - it just means the output shaft isn't pointing upwards on a more severe angle than stock.