I would like your views on this please if you have two minutes.

The soft graphite seals that are used to join the front down pipes and collector box, I understand they are there for a reason:-
1) to accommodate any vibration and thermal expansion In the system
2) to allow the system to be dismantled easily again.

I need to have my collars remade as they have corroded, would it be best to have the collars made to accommodate the soft graphite seal, or have them made so they just slide in with a bit of heat seal and tighten up?

What are your views?

The vast majority of aftermarket system have an interference fit there. I'd get them sleeved for such a fit and not bother with the gaskets

As above for two reasons.

1. They are difficult to reuse after taking the exhaust apart.
2. They are bloody expensive.

clear silcon is all that's needed, its cheap and it can then be used to fix leaky boots, roofs or your mrs kitchen sink etc afterwards with what's leftover.

Don't worry its made of silica (glass) which can handle very high temps been used in the automotive industry for years, that's why Wurth sell it :D

ibby4585 wrote: 2. They are bloody expensive.

I can get as many as I like for nothing. As long as I cut them myself

We use graphite gasket sheets at work and there's always lots of offcuts from when we've cut out a flange gasket