8v GTI exhaust help please

[PastyBoy]

Ok heres the deal

My Ibiza is now 12 years old and has 115,000 miles on the clock.
Shortly after I got it the exhaust started rattling against the heat shield.
Without proper facilities the best i could do to give myself to get underneath and fix it was to put the back wheels on a very large kerb and have a poke around.
On fixing the problem as a dropped forward off the kerb it caught the back back and pulled the whole system backwards
This pulled the centre section against once of the cross braces and caused an even worse vibration
Cross brace removed everything has been hunky dory for a couple of months, until earlier this week when a new rattle started.
Another section against another cross brace so i've removed that as well and the rattle has gone away

I had a spare hour so i popped by my favourite tyre and exhaust fitter and got it up on the ramps.
It would seem after 12 years and 115k of exposure the system is, in technical terms, knackered.
It's blowing in a couple of places, the baffles in the back box are gone and pretty much each join is corroded away to nothing.
This means everything aft of the cat is slowly moving backwards and at present the centre section has moved about 2 inches!
The fitter said that under normal circumstances they'd simply move everything back into the right place but mine is so rotten that won't be possible.

So now the part for you to get involved in:

Question 1
Given I've now removed all the rattle causing cross braces should the centre section come away completely from the cat there will be nothing to catch it and it'll fire off down the road behind me. This I want to avoid.

How much overlap is there generally in exhaust sections?
Is a complete collapse imminent after 2 inches of movement or do i have a while?

Question 2
Is £108 all in for a new cat back system reasonable?

Question 3
Is there a reason I shouldn't fit a back box from the 16V to my 8V?
(The online parts place i looked at had the valver one as £15 cheaper! )

Question 4
Given my very limited tools and skills is fitting an exhaust a DIY job?
It looks simple - undo the clamps at the joins, unhook from the bushes, pull away from the cat, remove, throw in bin.
Fitting the new one is the reverse surely?

 

[ibiza_95]

108 is a decent price for a new exhaust to be fair, id go for that if youre not bothered about any loud noisy kind of thing... i wouldnt bother fitting it yourself tbh, you can go to a little garage and get them to do it for 20 quid or so which in this weather is pretty logical really... i cant remember if the 16v and 8v have different bores i think they do but im not 100%

 

[AlpineWhite]

£108 is cheap.

8v and 16v have different exhaust diameters. You could use a reducing section, that steps the diameters down, but it'll probably wipe out most of that £15.

DIYing exhausts is a pain. The bolts may come away easily but you'll probably find that the sections of exhaust have rusted/welded themselves to each other. Garage job at this time of year, IMO.

 

[Cupra Kid]

DIYing exhausts is a pain. The bolts may come away easily but you'll probably find that the sections of exhaust have rusted/welded themselves to each other. Garage job at this time of year, IMO.

I can confirm that, tried it on the mazda and if the exhaust has been on a good lenght on time your gonna need some serious heat to get the pieces to seperate

 

[PastyBoy]

Thanks gents
Bit the bullet and had it done at the garage.
Looks sweet now that it's a shiny material again not a hugely corroded steel

Still managed to rattle against one of cross braces (I reckon the new system is longer than the old one) so removed that again.
Proceeded to take it on a trackday at Oulton the following day where it didn't miss a beat.
That said after half an hour on track when the temps were up it did start rattling a little bit and did managed to start melting the bottom plastic section of the rear bumper