General: Exhaust cracked-advice please

[binty]

Some advice please folks.
The exhaust on my 2006 D5 has cracked where the pipe enters the rear silencer. Its quite a bad crack and goes over half way around giving movement and it won't belong before it breaks.
It is the original exhaust and has done 148 000 miles, but all my other Volvos have had good exhausts well over 200 000 miles.
It looks like the back box is some sort of alloy and the pipe is steel, so I am guessing it has corroded due to the interaction between the two metals. I also guess this means I cannot get it welded? The pipe is very strong and the box undamaged, it is just at the point where they meet it has failed.
Does anyone know if it is possible to weld it at this point?
Secondly if I need to replace it, most suppliers are using Klarius exhausts. Are these any good?
(As a little aside these come with a two year manufacturers warranty as standard, but lots of exhaust shops (including big chains),only gives 12 months and charge for the second year warranty, cheeky monkeys eh?).
Klarius back boxes are £250, any idea what price a genuine Volvo back box is? I will find out next week but be helpful to know what they can be got for with discount.
Thanks