After all this time, FINALLY Luigi actually sounds like himself again! Basically it's Luigi's voice clips from the Western (aka: superior) version of Mario Kart 64 imported into Mario Kart Super Circuit. Would've also done the same with Wario, Toad, and Peach but they wouldn't import properly.
Database match: Mario Kart - Super Circuit (USA)
Database: No-Intro: Game Boy Advance (v. 20180816-092117)
File/ROM SHA-1: 9D327C030C3E2D9007990518594F70C3340AC56F
File/ROM CRC32: ED316E37