It's a bit of a mixed bag, the exhaust isn't great but ultimately it's gas tight and functional which is what it needs to be, my y pipe isn't much better, granted i didn't make it and wouldn't make something like it but it keeps the car on the road till i revisit it and ultimately function is all that matters to some people.
The mastic mount is a bit of a shocker and it should of been addressed or you informed but giving the benefit of the doubt it could of been a quick get through an mot fix that they intended to revisit later but for some reason didn't, i for one will admit ive pulled some proper stunts to get a car through an mot and then revisited things later to do it properly not everything is a deliberate attempt at something sinister or attempted shortcut.
it's hard to call but ultimately buying someone elses swap is always a mixed bag that anyone has to be prepared to redo as ultimately people have different skill levels and you can only find out you don't have the required talent or not by having a go in the first place which ill always be mostly in favour of