I was wondering if any of you guys know a credible business down my way who flashes/remaps/etc ECUs? Really keen for a 98 flash and/or Sports/vr-x tweak!

look for places that tune evos, generally they can do it.

... and/or Sports/vr-x tweak!
What are you expecting of this? The only 3.5l variant that had different tuning was the Ralliart - all other 3.5s have the same fuel and ignition maps, just exhaust and cam differences.

What are you expecting of this? The only 3.5l variant that had different tuning was the Ralliart - all other 3.5s have the same fuel and ignition maps, just exhaust and cam differences.
I've been told that the only difference between the exec and Sports models were the rear muffler and ECU?

ecu is the exact same.

ecu is the exact same.

So only rear muffler and cams changed?

So only rear muffler and cams changed?
The cams changed from #4 to #6 at some point - I'm not sure but it may have been in the changeover to the J series from the H series. Before the changeover all 3.5s had #4 cams, and after the change all 3.5s had #6 cams (except of course the Ralliarts which had #7s) regardless of Exec/Sports/VRX/Verada etc.

So for a late build TJ, the only driveline difference between an Exec and a VRX is the muffler, which was claimed to be worth 8kW - engine, ECU and exhaust system from the engine to the muffler flange was the same.

contact Merlin. He's based in Sydney

He did my car and it is great. All round awesome results