Talon Diffuser Dummy Tip Issue

[Styx]

So the talon rear diffuser I ordered just came in yesterday, and I've run into a minor problem when test fitting it.

My car already has a 3 inch exhaust tip, but the dummy tip that was supplied with the diffuser is only 2.5 inch. Obviously I'd want them both to be the same size, so I thought about buying an extra 3 inch exhaust tip to use as the dummy. Something like this: https://www.supercheapauto.com.au/p/str ... 31475.html

I was wondering if that exhaust tip is all I need? If so, how would it attach to the diffuser?