saab 2.0t in a jimny

I'm a shepherd and regularly tow a twin axle trailer full of sheep at the maximum 1300kg on road, on farm tracks and off road in fields, certainly it's not quick but what it is capable and has never offered a refusal. Don't forget that with a trailer on your speed limit is reduced anyway. Also even without a trailer a Jimny is better suited to a meander taking in the surroundings rather than blasting from point to point.

I've done a couple of 1.6 swaps (105hp Liana engines, although I'm sure they make a bit less with Jimny manifolds) and I use my Jimny's primarily for towing. I deliver loads of firewood that weigh around 1,200kg. My 1.6 Jimny will happily tow that load at 60mpn, more if necessary. It will tow it off-road fine too, but always runs out of traction before it runs out of power (that's with a locked front diff, rear limited slip diff, mud terrrain tyres...)
Without the trailer on the car will happily cruise at 85mph. With ~300kg of motorbike and trailer on the back you could go anywhere you wanted to.

More power always seems like an attractive thing, but if you go too far you will have other issues. The whole lightweight nature of the Jimny is built around having high revving, low torque engines. I heavn't had any drivetrain issues with the 1.6 but if you start doubling the torque output you're going to break things. If I was to swap to a more powerful engine I would go to a higher output NA engine like the 2.0 Ford Duratec. It's still 150hp, but it makes it in a more linear way than a turbo engine. It's also a common choice for engine swaps in RWD platforms so getting a compatible gearbox, sump, manifold etc. is easier. And it's lighter than the Jimny engines.

Having done a few swaps and even designing and selling motor adapters for the G13 swap here in Norway, I must say the ease of the G13/G16 and the even easier M13/M16 swap (more or less bolt on) makes any other engine swap very undesirable.
I have encountered alot of mishaps with my drivetrain that may have something to do with the small increase of torque and power. have been changing the rear diff, gearbox, driveshaft and now my transfer case makes a bit noise. More likely it is connected to my style of driving.

for offroad use there is seldom any use of more power. The gearing and tire(size) combo is more important. For on road use with my liana engine I never had any problems following traffic pulling my daughters horse carriage around for competitions. should weigh about the same as a motorbike. Even been pulling 1000 liters of water and other loads of around 1000kg like the empty ifor williams horse box. it is ok but the hills are longer with 1000kg. for 500kg no problems.