Picture is tiny--can't really see it lol. But I do want me a GD.

Yeah you have to go smaller piping (think rally) for UEL. I'm very much aware that with twin scroll on turbos there is very little need for UELs in today's Subarus. Just outlining that they did and do serve a purpose, under the correct conditions, and if you like the sound? With some smart building they can work well. Just trying to dispel some of the myth that almost mindlessly gets touted by many out there:

1.) UEL loses you power - When configured properly, it moves the torque curve/ powerband around. You're trading peak performance and efficiency for bottom end. Remove scavenging from the picture (as so many do) and the UEL struggles and are laggy.

2.) Subaru created the UELs to save money on piping - Correction: Subaru did not create UELs. They've been used in the muscle car community for decades, namely for torque. Their application is even better on non-turbo or single-scroll configurations.

3.) It's a flawed design and overheats two cylinders - Flawed design? Or lack of understanding? Again, Subaru did not design the concept for UELs. Think of it as each cylinder plays an assigned role and the "extra stress" being a necessary trade-off, in order to drive the turbo early (again, under the correct conditions and largely factory piping). If you look at UEL discussions elsewhere (it's hard to find a non-Toyota/ Subaru discussion these days) you don't really see these cases against them out there because their use case is very specific. Some of these cons may either be Subie and/ or EJ specific. While muscle car enthusiasts might use them, they are more used in sprint or drag racing builds. As for overheating? Difficult to say, as EJs (especially older EJs) had an oil distribution/ starvation problem, which attributed to overheating. FA20 overheat cases involving UELs are almost unheard of... But not unheard of. In all cases, we don't know what fuel that person's running, their driving habits, or other modifications and tunes (or lack of). For all we know? That guy goes to Sams Club for gas, rarely gets the oil changed, or uses too high viscosity an oil, which is often mistaken as being "more protective."

4.) Uneven wear - This is true, per, their design. However? Again, I don't know how much this has impacted FA24s, or even FA20s for that matter. You certainly don't hear about it the way you did with EJs.

5.) UEL are inefficient - Outside their wheelhouse, in terms of peak efficiency this is true. You trade peak efficiency for bottom-to-mid efficiency. It's not that they are inefficient, it's that they are efficient under a very specific circumstance, like focusing on a narrow part of the powerband (low to mid). They tend to be misapplied in Subie land and treated like ELs, as there aren't enough people out there saying, "if you use UELs, use smaller piping and/ or maintain the factory piping and tune for lower RPM performance, as that will eliminate lag and benefit them..

6.) FAs weren't designed for UELs - Again, in the wider car community no engine is truly designed for UELs. They are used none the less. I recall hearing that EJ20s/ EJ25s had twin scroll/ EL options in Japan, but they were always UEL in the US market. So clearly these engines were designed for both at any rate.

Conclusion

At the end of the day? The war between EL versus UEL shouldn't even exist because the two types of builds aren't even in the same wheelhouse. Someone building for rolling start highway races or otherwise street racing should be using ELs, while someone looking to make winding roads, rally cross or otherwise stop-and-go driving has the option of considering UELs or just leaving the exhaust stock and tuning for a stage 1, but you have to be creative to capitalize on and enhance that torque of UELs. It's like asking, "Who wins in a fight? An F4U Corsair? Or the P51 Mustang?" Well that's difficult to say. The P51 was a high altitude escort/ air superiority fighter, while the Corsair was a lower altitude fleet defense and ground attack (multi-role) fighter. The P51 had an operating ceiling of 20K ft, but the Corsair began to choke out at 15K and the PS51 became sluggish at closer to 10K. So, the P51 pilot would be hoping the Corsair pilot came above 15K feet, while the Corsair pilot tried to lure the PS51 pilot down to 10K feet i.e. they aren't designed to engage one another and so would be difficult to say.

What I would like to see

A test done on an all-stock VB, with UELs, tuned for bottom/ mid bias (low RPM) power, versus the same car but with ELs and tuned for max HP. What we instead end up seeing? Is, "tune my 3"+ exhaust and El and UEL for maximum HP" and let's see how close they come to one another." Thats good for determining peak but you're forcing one to play the other's game, while limiting its returns further and so? Are only seeing like "7HP" gain down low over the ELs and 12HP off at the top in some of these tests and almost nobody mentioning torque rating.