For the last several years, often my work days are spent in the company of Porsche GT3 Cups and GT3-RSRs. The 997 and 991 3.8 motors, which make 500+ HP at 8500 rpm, have a glorious wale at full song. While the note of a Porsche flat six is one of the truly iconic car sounds, I was never that taken with the sound of the Porsche flat six until this engine.
However, the modern GT3 homologation formula favors turbo charging and thus the previous normally aspirated engines will be usurped by smaller displacement turbos. The new Ford GT is a turbo V6, Ferrari has a new turbo engine replacing the 488. While these are cool engines and technically advanced they are relatively low reving engines that don't make inspiring sounds.
The common characteristic of all of the great sounding racing engines; V12s, straight 6s, 60 degree, even-fire V6s, etc..., are they have smooth melodic notes. The by product of a smoothly running engine. The Subi Boxer engine's note is counter to that. The odd beat sounds more like a misfire than a performance engine. No wonder the Subi is propular among the counter culture?