I liked the Cobra 75 I had in my JK (with external speakers in the roll cage) so much, that I put one in my TJ too. But over the course of the last 8 months, both Cobra 75s stopped working. They hate dust, so don't make a good Jeep radio IMO. I should have did it right the first time and installed a "real" CB.
I had a peaked and tuned Cobra 29 in my 4x4 Suburban, so I mounted that in my JK above the rear-view mirror with a custom mount attached to my RockHard cage. Great range and features, and the Road King noise canceling mic is sweeeet.
IMHO, I wouldn't waste the money and cut up/drill your jeep to install a 75. Range, speaker, and quality are lacking in that unit.