How long have you had it?
Personally, I’d clean it really well, and make sure the 4 (I think) Torx bolts are good and snug, right is tight.
And give it 2 months and see if it’s a serious leak and back.
I’m not familiar with a rebuild boot, and the NSG the shift tower is expensive because of all the detentes etc in the shifter.
The B&M is way more expensive but a great upgrade.
Also, if you get one, pay close attention to the year, because the Bend in that shift for the JK that had that trans for a long time and far more prevalent, it doesn’t have that same bend, and it’s a PITA that it fits different in the 05TJ.