A Cummins 4BT would be awesome. I love the sound of those little engines.
But to be honest, the Cummins doesn't seem to be worth the hassle. More work involved and also, incredibly expensive. A decent 4BT costs around 2k-4k these days; much more expensive than the Benz. I can get a complete running car; a 300d (Turbo OM617A) for anywhere between 300-800$ and most of the time they have transmission issues/no problems whatsoever with the engine. Many of them have around 200k miles, which in OM617 miles is like 30k on a regular engine.
Also, the Mercedes diesels are so cheap that for the price of the cummins, you could buy like 3 of them, scrap the 300d's and still have a assload of money left over for lift kit and extra goodies. Thats my kind of engine!
I reallyyyy would love to put one of these in a 1995 Grand Cherokee, but they didnt come with the 5-speed AX-15 as an option. A black one with 6.5 inches of lift, 33's, all blacked out, deep window tints, roof rack, Navigation, Mini fridge, Road armour bumpers, HID hella's.... Dream Jeep... Haha
1992 YJ, 4.0 HO, 5-Speed (AX-15), 2.5" lift, 31" tires, Sony sound system, w/ pioneer sound-bar, copper-red paint, Loved it. Miss it. Sold.|1999 XJ. The "Cheep". 4.5" RC lift. 33" BFG MT. Train Horns. 2wd to 4x4 build. DD. Sold.|2003 WJ. 30" Michelin AT's. Curt roof rack. Train Horns. Stock. Soon to be lifted. DD.