Firstly welcome.

I haven't a clue if they'll fit or not, you might find a definate answer on a Nissan forum, but if 16" wheels are not specified for the X trail at all then as an unspecified size you would have to tell your insurer of the change.

If they did fit, and i have no idea if the spigot PCD and offsets are compatible even if they clear the hubs and calipers, then you'd still need to run the tyre sizes through a tyre size calculator (easily found via any search engine) because there might be a big difference in rolling radius.

Carbibles is a good source of such calculators and he will explain the other terms i mention far better than i could,

You might even find someone on a Nissan forum doing the car swap the other way round who might do a deal with you.

However, assuming the Xtrail is a 4x4 version, i haven't a clue if they do a 2WD, then unless you are going into central europe during the winter where winter tyres are a legal requirement or you live somewhere really steep or remote i would expect your new car to be up to British conditions on its supplied tyres.

As for a good winter tyre, i'd get anything from a known respected make, preferably european avoiding Chinese and similar, that happens to be on offer at Tyreleader or similar site.

Edited by gordonbennet on 01/11/2015 at 23:05

Its not my place to do so but I can't stop myself commenting. This surely is a forum at its finest - helpful and courteous replies to a newcomer ( welcome ).

I strongly recommend you to heed GBs advice re Insurance : they will often try to escape liability on any prertext.