There's 2 version of Fray. The blue spine one and the pink spine one. Pink spine requires the Turbo-R.
Besides the voices, it also allows you to use the fastest speed setting. The fastest speed setting only
works on a TR. The manual clearly states this.
I know that (I have both). Thats pointless though, and not worth buying the Turbo R at all. The Turbo R is really only for collectors, or people who don't know any better and buy into the whole OMG R800 MAKES ALL THE GAMES BETTER, which isn't entirely true. All it will do if you force a disk game into R800 mode, is prevent slowdown. There's no code in Aleste to make it add more bullets if its an R800. Like I said, thats just a bug jacking the difficulty setting up. You can play that uber bullet difficulty on a lowly MSX2. I checked, just to make sure I wasn't delusional.
Cartridge games can't even use the R800, so even if you play Manbow on a Turbo R, you aren't getting anything special. Its a placebo if you think the games playing better all the sudden. The R800 didn't exist for coders to write for when some of these games came out, so how could they have possibly planned for R800 special modes.
How fast do you really need to play Fray? The default speed is plenty perfect. Its as fast as Xak.
An MSX2+ is the ideal game machine, recommended by nearly all MSX afficionados (including myself). If you can't find one, an MSX2 retrofitted with the new 2+ video chip, and an FM-PAC will do just as good. So either get a Japanese 2/2+, or the Philips NMS82 45/50/80 if you're European.
The machines themselves are nice (HBF1-XV: built in MSX-MUSIC, rensha turbo and speed slider, disk drive. V9958..), and when applicable, games use the v9958's horizontal scroll register instead of the other smooth scroll method used on the 9938, which makes it look a bit nicer visually. On the 9938, you might notice flicker on the ends of the screen as it scrolls. You'll see tiles on the left that will then show up on the right as you're scrolling right, or vice versa.
However, if the game didn't already scroll smoothly (be it with clever V9938 use, or the V9958's happy hardware improvements), a 2+ or a Turbo R isn't going to automagically put that in for you. Thats why Gall Force still block scrolls on a Turbo R.
Look up the actual game library for the Turbo R. Its the Super Grafx of the MSX world.

I like Tir nan og, Seed of Dragon, and Illusion City (<3), but I'm also the type of person who will pay 600$+ to play one frigging game.
The only way you should buy a Turbo R aside from collecting purposes, is if you can locate one for a reasonable (MSX2/2+ comparable) price.
You can nab a boxed 2+ for <100$ though, so I don't see that happening.