Samft that was an epic response man. So much info. Thank you!

Tourismo the grand has 4” lift plus long arms front and rear so I’d been getting into some pretty serious tracks. The bloody thing is just off the road so often that it’s almost not worth having.

So all advice is pointing to the 3.6. Just to throw another question in there while we’re at it, how does the diesel rate against the 3.6?

Dear god...don't ask that ;) or this will become another 'are CRDs worth it thread' haha

Nah, I'm a CRD owner, and we all seem to love them until something goes wrong, then it's like F'ing CRDs. I have a great mechanic who eases my nerves of parts availability or engine issues but not all are so lucky.

Mine is auto, fully locked with 35s and about 4inches of lift. It's largely unstoppable, and I still get 11.5L/100kms on long flat drives (with all terrains and a roof top tent).

I haven't driven the equivalent in a 3.6 but I doubt they have the low RPM chug along ability and I know they become fuel hungry with 35s.

CRD's can be a bit limited for engine parts (and online advice) because the US doesn't get a CRD JK

I think if you care about how they feel on the road, the CRD drives like a truck but I think the 3.6 revs up more like a car.

I'm not convinced either engine will last longer than the other. The CRDs are meant to be better engines for towing and will use significantly less fuel, however they do get hot (the manual less so, but I believe their clutches are a weak point)

Most people are quite happy with the 3.6 though so long as they don't regularly tow (only the 3.8 was available when I bought mine FYI). You also get all the US engine parts (superchargers!) and can do a V8 swap a lot more easily if you ever wanted.

I believe the easiest way to decide if a CRD is worth it for you is if you're particularly bothered about fuel economy, or sometimes more importantly 'range on a full tank'....or if you will tow much.

Otherwise I reckon the pros and cons of either engine are fairly well balanced.

Beautiful! Thank you very much to everyone who contributed. I came very close to buying a 3.8 rubi with 80,000 ks but it had a bit of rust and a rear diff noise so I let it go. I think I’ll keep an eye out for a low k 3.6 and put the work into building it. It’s not what I really want to do at this stage, but it’s the most far sighted option. Hopefully I can find something and get it track ready in the not too distant future!

Just keep in mind the 3.6 and NAG1 auto are really good together, but the actual performance is still dependent on the diff gear being right for the Tyre size.

I have a Rubicon 2-door which is slightly lighter. 4.11 gearing has worked well with bigger tyres. 3.27 diffs and 4-door would make it feel underpowered.

Kiwi- yeah so I guess what I was really asking in my OP was, do I get the rubi and suffer with the 3.8 or do I get a 3.6 sport and then install lockers. If I was putting lockers in I’d regear while I was there so it’ll end up being an expensive upgrade.

Anyway, my decision is made. Yesterday I put a deposit down on a bright yellow 2015 sport with 45,000ks for $28k. It’s very clean, never been off-road and came with a stubby bar and rear bar, lights, winch and a bunch of internal additions. It’s more than I’d intended on spending but I’m very happy with it and it’ll make a great platform to build on.

So given that I’ve already overspent, does this sound reasonable to start with? Pick up a second hand 2” spacer lift, put on some 35s a snorkel and some discos. From there I can put a bit of research in and work out a permanent solution to the lift. Would it be silly to go straight for 35s without regearing or strengthening the front diff/axle?

Congrats on the purchase
auto or manual and 2 or 4 door?

not sure you can go to 35s on stock rims?

FYI the AEV rims are made to be hub centric on the wranglers

wranglers are prone to shakes and wobbles (especially with 35 inch muds) so having a hub centric rim removes one point of unbalance. I didn't get AEV but I would have if I had known this.

I have no experience with spacer lifts but a 2 inch coil and shocks lift might last you a few years and wouldn't cost much more, it might be worth doing that while you sort your diffs and lockers.

2 inch lifts are incredibly simple, but as soon as you go to 3 inch you begin needing to change geometry etc.

If you're going to 35s, a 2 inch lift will probably do you well for a long time.

You could always grab some new rims and 35s and trial them. If you're cautious I think the D30 will be fine. that way you can swap back to the stock tyres easily if the 35s sap too much power (before re-gearing diffs).

You need to decide if you're going to stick with the D30 (meaning strengthening and re-gearing) or buy a built to order D44 with the gearing / lockers built in

Modifying the D30 will mean more time in the shop for your vehicle i suspect

I personally would save up for a built D44, it probably wont end up costing much more (especially when you consider labour and time in the shop) and you'll have piece of mind that it's significantly tougher (which it sounds like you'd make the most of).