My brother in boost, thank you for so beautifully demonstrating my exact point that people with evo 8/9 don’t appreciate the evo x because they are not familiar with the platform. While the 4g63 is iconic and reliably proven, it’s outdated. (Not) Surprisingly, a “modern” engine designed in the 2000s is better than one that dates back to the 80s, what a shocker…

The main difference is going to an all-aluminum block (which btw all modern sports engines are nowadays). I’m not going to focus on the weight (although there’s benefit of reducing engine weight out front) since the evo x is a much heavier car, however aluminum does provide much better thermal efficiency, which increases heat transfer to the cooling system to better keep temperatures in check. This is coupled with more modern designed (and better) coolant and oil passageways. The evo x has a significantly better flowing head from the factory. This coupled with Mivec on intake and exhaust side dramatically increases low and mid range power. When you’re looking at your pretty dyno charts, the evo x will have more available power underneath the curves at the same peak hps and provide better response. There’s a lot of minor changes as well as moving to bucket-over-valve design direct valves (eliminated hydraulic lifters and rockers arms) that decreases failures at high rpms, semi-closed block (instead of open) to be better against cylinder wall distortion at high boost, four bolt main cap to ensure crankshaft remains in place (fight against “crank walk”), two-piece oil pan design to help block rigidity to prevent twisting and flexing at high rpm, fully free floating pistons. Lots of these changes eliminate or fix issues with the 4g63 (heads lifting, balance shaft, mains with the cast iron girdle). There’s really so much more and that’s not even touching on the other parts with the engine (an actual decent intercooler from the factory, twin-scroll responsive turbocharger, etc.).

Like you mention, yeah the exhaust side is now on the back of the engine, which makes it a huge pain to work on it (ask anyone who’s changed their exhaust manifold on the evo x…), but there are a few benefits. Those are mainly shorter exhaust pathways and the downpipe no longer runs underneath the oil pan (not great to have hot exhausts heating up your oil), and you can better isolate the heat or the turbo and exhaust in the back of the car with heat shields (instead of it just heating up the entire engine bay).

4g63 main benefits remains that it’s simpler, “ol reliable” and can handle huge power. You can get comically high hp numbers out of that engine but you need to sleeve the 4b11 once you start going past \~450hp. I’d argue that a large chunk of evo owners (maybe even most) just do full bolts on or less, where you wouldn’t be exceeding that 450hp threshold anyway.

This is all not even touching the more advanced AWD system, the chassis stiffness (even the base lancer of the evo x generation is stiffer than an evo 8/9), etc.

You may prefer the evo 8/9, I can’t argue against that, but saying that evo x only selling point is mivec on intake and exhaust and nothing else is just false. There’s really a lot to like in the 4b11 platform if you really dive into it.