4 speed to 5 speed

I have a 4cyl 87 Jeep with a 4 speed manual tranny, I was wondering if I could swap in a 5 speed manual. I use it as my daily driver and the 5th gear would really keep the RPM's down on the highway. I hate when I am driving and its whining. What can I ***  

You have an AX4 transmission. You can pretty much bolt-in an AX5 (five-speed) from a later model Jeep (up to '93 if you want to retain the internal clutch release). The '94 and later AX5 trannys use a different bellhousing and a more desirable external slave cylinder for the clutch.  

Would it be a direct bolt on or would I need to modify anything? Right now its bone stock but I do plan to do some slight tweaking in the future, like maybe a turbo and a 3" lift but nothing too drastic as it is my daily driver.  

Like I said. Should pretty much be a bolt in. But having worked on lots of Jeeps it never goes that easily.  

Thanks, now the hard part, finding one to bolt in... Most of the junk yards around NJ are cleaned out of Jeeps, but I keep checking.