Wow! What a great guide! Well worth joining the club for! LOL! (Modesty!)
You can't fail an MOT if you just bolt it on but the crossmember is welded on for a reason.
It connects the chassis legs and gearbox support member together. The parts aren't particularly strong on their own but when welded together they are.
Put simply, if the car functioned the same with the crossmember just bolted in why would Nissan bother buying expensive robots to weld it in?!
Even if you fit the new one yourself and run it round to your local friendly garage and have them weld it in, they shouldn't charge too much as most of the labour time is spent removing the old one and putting everything together again.
