Modern Vespa

What size are the three Torx [sp?] screws that hold the silencer to the bracket? They appear larger than the Torx driver in the toolkit.

They seem awfully tight. Are they easy to remove?

I think I need to change the graphite collar thingumy as the exhaust is making a lot of noise and I can feel exhaust gases puffing out underneath where it joins the manifold.

P.S. only 5,000 miles; never been removed.

The size is T40. If they've not been off before they may need some 'persuasion' to come undone, but as long as you use some anti-seize when replacing them all should be fine thereafter.