Disc swapping is easiest on Model 1, but it's doable on any model. There are several techniques with varied levels of effectiveness, I personally do the double-swap as described here:how do you get Disk swapping working?
and how do you know which model you have?
EDIT# FIXED*
http://www.racketboy.com/retro/sega-saturn-swap-trick
First you load the TOC (table of contents) from your copy, then swap for an original disc, load ring data, swap again and the game should boot. It's even easier once you consider that the Saturn will remember the TOC upon a reset, so you can just fully load with a backup, reset the system while swapping for the original and then perform the final swap. It's easy enough, all you need is some tape to disable the lid button and a screwdriver to open the system, no fancy game bits required.