I bought a kinetix plenum on a whim then decided against it purely on how it fitted and looked then got a plenum spacer and painted my oem plenum gloss black.
+1 on the cat.
Your car is definitely a pre facelift DE for sure. However I'm a little confused on the oil gallery gaskets failing as I was to understand that was a HR problem.
It will be more than likely what is k now as the W brace they tend to turn to dust.
Heres a quick link to torqen. Other traders on here stock them too i.e. Tarmac Sportz, Zmanalex to name a few. Have a look and search in the traders section.