First off it depends if you have a N/A or turbo 4.2 or a 2.8 Turbo.
I've heard that there can be some very minor differences in front pipes for N/A motors making them difficult but not impossible to fit. From what I can see the difference in the short and long wheelbase exhausts is in the middle box ( it has longer pipes)
If your flexy has gone on your front pipe, the flexy bits are widely available just weld or clamp a new one on.
There's loads of exhausts on ebay, some very cheap suppliers in Germany too that will post to the UK for about 12 quid.