1. The radiator is the same, but mounted differently. Make sure you keep the top and bottom intercooler mounting brackets from the 940. The top ones will have to be bent a bit to make a proper fit. You'll also have to cut the 940 radiator hoses on the end that connects to the radiator as they will be a bit too long for the 240 engine bay.
The fan situation is annoying. Once the radiator is mounted, it sits a bit higher and the shroud no longer fits around the fan properly. I love the nostalgic "woosh" and reliability of the clutch fan, so opted to keep mine and modify the shroud to work. A bit of work, but probably no more than fitting an e-fan, and it arguably cools much more effectively. Used a grinder and very steady hand to shorten the shroud and then cut out the parts where the fan hits. it looks stock
2. Computers plug straight in.
3. 850T injectors are a higher impedance injector which is great because they slot right in, no need to wire in resistor packs etc. Make sure your FPR is rated 3.0 bar, too. My 240 was fitted with a 2.5bar.
4. Probably wire in a boost gauge. Even if you intend to run it stock psi, just for piece of mind and troubleshooting etc.
5. I would find a way to keep the 940 intake and airbox, and install it in the 240. You might need to swap the coolant bottle and delete the washer bottle to make room. I made a custom intake with conical k&n style filter, but the cbv and induction sound is really loud. I've noticed a lot of turned heads!