Yeah, seriously, just dump 4K on a 60...............
Wow, I hope that's gold plated or something.
If you've already got a bunch of $$$ in your front axle, maybe the 8.8 isn't such a bad idea as long as you keep your tire sized appropriately for the front axle. If you haven't spent any money on either axle (front or rear), I'd suggest taking a look at the below. If you're wanting to run 37" tires (assuming you're actually wheeling trails that require such tires), your stock front axle is a total pile. It's barely serviceable with 35" tires, IMHO. It's a great axle for 33" tires, IMHO, though......and there's really nothing wrong with 33" tires.
Random Thoughts on heavy axles.....
I'm not going to argue against the 8.8. That's a decision you can make. Here's my take, esp. on a coil spring rig like a TJ or similar. Why upgrade the rear axle more than once? You'll spend some $$$$ setting up brackets and all that is associated with your 4 link no matter what axle you get even if you can do it yourself. I'm a cheap ass and I'm not stopping with an 8.8 even though I know someone that had good success with one with 35" tires. The axle doesn't cost much compared to the labor/time/equipment to set it up esp. if you're not doing it yourself.
If you're 100% sure you'll never see tires bigger than 37", maybe the 5 on 4.5" bolt pattern is for you. I'd submit that that is a pretty wimpy bolt pattern for something with that kind of leverage, though. I've never known of a failure, but there's got to be a reason 3/4 and 1 ton trucks don't run 5 lug. I'm going with the automotive engineers studies and going to 8 lug (and they don't spec tires bigger than 32" or so) on 'severe use' type vehicles.
If you're running 37" tires, is your front axle up to the task? I'd say no as I spent a TON of time (oh, and $$$$) fixing and refixing and rebuilding and refixing a super cool reverse cut, non-disconnect D30 in the front of my 'light' XJ. Why not run a matched set of 8 lug and never worry about it again?
Mine was a purely financial decision. It costs money to get to where I can wheel (fuel, honey-dos, lodging, vacation time, etc.). I can't afford to break my junk and then spend more $$$$ fixing it to get it off the trail only to have it break again the next day or the next ledge or the next trip or the trip 4 times from now. As all these SuperDutys and Cummins trucks start leaving service, is it going to be hard to find a D60? I kinda doubt it. Do you think you could buy a MATCHED set of axles for $1000-1500? Is spending $800-1000 on alloy axles and CTMs (or whatever) kinda silly if you can buy a replacement front axle (the whole thing is BEEFY--housing, tubes, balljoints, axle shafts, ring/pinion, axle joints, etc.) for about the same cost and have similar strength to the 'upgraded' D30 or D44? I'm not trying to tell you I'm a bad ass because I have a front 60. I have one because I BROKE (many times) the D30 with 35" tires. The front axle is the weak point in all our rigs (D35 equipped rigs, that could be debated). Why let that dictate your rear axle?