I'm thinking Ian probably has the info you need on this. He has (for one) the parts info which he shares regularly on the forum.
I owned a 2000 Tracker but to be honest, never really looked at the exhaust manifold (with heat shield in place) as the exhaust never gave me any issues. Actually, nothing on the truck gave me any issues. My 2002 Trackers DO have the tubed exhaust manifold on them. I discovered this when searching for a 2Liter header for one of my trucks. The only ones I actually found were out of Australia, I believe they were "Hurricane" brand headers. Anyway, when replacing an exhaust donut I noticed how the factory tubed exhausts DID look like mini headers and figured my power gains from an actual after market header would be minimal (given the cost and freight from Australia) and opted not to pursue the aftermarket header ALTHOUGH I will also say the Hurricane sales persons were very helpful when discussing my application need. I decided their 2 liter header (built for right hand drive model GVs WOULD work (clear the steering shaft) on my Tracker.