You will not get anything that will bolt up. Just about every brand will make their cats different to suit their own headers. You will need to cut and weld what ever you get.
You will need an O2 sensor extension for the LHS, the RHS will reach.
Ummm.....you will also probably need to get a new cat back as well, because the XForce will sound like **** once you fit extractors and high flow cats.
Trying to do things on a budget mixing and matching brands just doesn't seem to work on the VE. You will fit the extractors, spend the money on cats, modify it all to fit, then find it sounds like crap and have to spend more money trying to fix it.
My opinion, piss the XForce off and fit a decent cat back. Depending on your budget, I wouldn't even bother with the Pacies, I am doing a complete package deal up until the end of December for extractors, cats, the cat back and all nuts, bolts, gaskets and the sensor extension loom all for $2360 shipped.