Given that the R34 is a great performer, why was it discontinued?

Back to SiR, I pretty much believe it's the easier car to drive compared to an Evo. It only has an NA engine with FWD as opposed to turbo with 4WD. It takes some time to master the launch of the Evo. I think it has something to do with clutch burning, so proper and timely release is required. In the Honda, practically anyone can launch it respectably. Light clutch, slick shifter, and an engine that only needs revs - you're up and running.