I have my eyes on the Banks CARB approved turbo with intercooler. Supposed to be pretty easy to bolt on. The turbo is little over $3k, the intercooler is a little under $2k. I’m guessing it’s a weekend install. I have a 30k mile complete 4.0 sitting in the corner of my garage. I’ll probably do the swap first since I feel better about turbocharging a motor with 30k vs one with 123k... I chose 4.56 gears over 4.88s with a turbo in mind.
If you can afford it, do it, you'll be glad you did. I installed the turbo kit by myself over a weekend (before they offered the intercooler) and it was very easy. You do need to weld a bung on the oil pan for the turbo oil return, but other than that, you only need basic hand tools. Since my exhaust manifold was cracked in two places, I went ahead and replaced it with the Banks header. I think it was actually harder to replace the header than to install the turbo (some of the exhaust bolts were really difficult to get to).
I kept a careful eye on intake temps (it got over 200 on a hot day) so as soon as the intercooler was available, I added that. I also added the Banks cat-back, so they must love me as a customer.
My TJ had around 30k miles so it was well broken in but should still have a long life. Having twice the power has transformed my enjoyment of driving it. I hadn't gotten around to re-gearing it, even though I know I should since I'm running 35"s. With a manual I could only use the overdrive 6th gear on level ground, and had to downshift at any uphill grade. Now I can use 6th pretty much any time I want, and I don't feel the need to re-gear. I've got all the power I need for pretty much any situation, and can comfortably cruse at 75 on the highway.
$5k is a lot of money, but a local Jeep guy paid someone $12k to install a Hemi in his Jeep so, it doesn't sound bad compared to that.
For the money, I got a system that doubles the power of the Jeep, I installed it by myself in the garage with basically hand tools in a little over a weekend, I keep the reliable factory engine, and it's smog-legal in California. My gas mileage actually went up a couple of mpgs, I think because previously I was pushing the engine harder to accelerate with 35"s and stock 4.10 gears. I'm thoroughly happy and would recommend it highly to anyone interested.