I'm not sure, but on my NTSC system it automatically forces the games into 60Hz NTSC output - I've got PAL copies of Burning Rangers and the first disc of Panzer Dragoon Saga, and to my surprise the 4-in-1 set them to 60Hz NTSC. AntiPasta I believe had one as well, maybe he can tell you.
The output doesnt change. Any imports you play will have ugly bars on top and bottom of the screen and will run about 20% slower. If you have a PAL system then it will run at 50hz. the 4-in-1 doesnt affect the PAL/NTSC mode. afaik no cartridge/cd can change the output, the only way to change it by modding the Saturn.
urgh, looks like i want a JP saturn then - Looked at the mod and it looks pretty damn tricky to do...
It's not that tricky, in fact, if you have a Model 1 Saturn it's very simple... just dont try it with a 3mm soldering gun like I did. I botched it and now my video output is blurred :smt1069 And get a Japanese Saturn, certainly beats the 4-in-1 I think. And no it doesn't force the output, as it is governed by the system itself! So if you play PAL games on a US Saturn the output will indeed be 60hz, but in case of PAL optimized games like Nights (thank god), Story of Thor 2 / Legend of Oasis, Duke 3D or whatever the screen will be stretched beyond its borders.
Not only streched but they will also play about 20% faster!! Try VF2, Daytona and Sega Rally (all PAL ) on a NTSC system, its awesome!!