Mine were easy to fit too. As Dead Eye said, Wd40 does the trick. Make sure you get all necessary gaskets before you begin. I replaced the nuts & studs aswell. If you want to replace the studs, extracting them can be a bit tricky but again WD40 treatment helps.
If you replace the original long nuts with ordinary nuts, I'd recommend that you cover any exposed thread on the studs with further nuts. This is because if the stud corrodes, even if the nuts are ss, they are not going to come off easily in future if the thread is rusted up. This is why the oem nuts are weird long ones that cover the ends of the studs when fitted. I replaced them with some new oem ones in the end.
I got Motad downpipes & happy with them.
If you replace the original long nuts with ordinary nuts, I'd recommend that you cover any exposed thread on the studs with further nuts. This is because if the stud corrodes, even if the nuts are ss, they are not going to come off easily in future if the thread is rusted up. This is why the oem nuts are weird long ones that cover the ends of the studs when fitted. I replaced them with some new oem ones in the end.
I got Motad downpipes & happy with them.