I have finally made my decision on which lift to get, going for the RE 3.5 Superflex.

I know RE recommends a SYE but is it need or does it very from Jeep to Jeep?

I am fairly sure its necessary due to drive shaft angle. You may have to go with the t-case lowering kit to get you by if your not going for the sye right now.

You'll need it. I put a 3.5" kit on my tj a few weeks ago. Actual lift came out to 4" over stock. Even with a SYE the U-joints were at such an angle that I had to put a CV driveshaft in it. Without the sye, the problem would have been even worse. While you are at it, it is the perfect time to go with a 4:1 gearset in the t-case as well. Yes, it costs more $$$ than you planned.....just empty every pocket.

it is different for every Jeep. I have the RE 3.5'' SF and got close to 4.5''. I droped the T-case during the install and i don't have any vibes at all(no SYE). i would say lift it, test drive it, then if you need it order it but if you don't you saved some money

Well in my case I had no choice but to do the SYE & CV shaft due to my Skidrow Eng./Trans. skid plate. I could not use the T-case drop kit since the skid plate uses one of the front lower control arm bolts plus clamps to the existing t-case skid plate. One other issue was the Dana 44 diff. It make for a shorter shaft already. Your looking at probably one of the best kits but be prepared to (JEEP) as said above to Just-Empty-Every-Pocket. Nature of the Beast.

B&T TJ

As I did exactly that same deal to our yeollw TJ . We did the nth Deg belly up , no way to get around that tcase mod and DC driveshaft. I thinnk Tcase drops are a joke:-)