I've actually driven two different cars that both had these same clutches in them. The stage three was a good, strong clutch. The pedal feel was a good amount heavier than stock, and for someone not used to driving it (me), it felt like an on/off switch. My buddy had lots of chatter with it as well. But that thing took unbelievable amounts of abuse, at well over the rated HP (he was making about 790 rwhp). Never skipped a beat.
Another friend has the McLeod RST in his car now and it's got the quirky feeling of a twin disk that's easy to get used to, great for daily driving and holds power really well. It seems the RST is a good amount more than the Monster, but if it were up to me, I'd probably spend more money and go with the RST just because I couldn't deal with driving a stage 3 in any sort of normal traffic scenario. On the highway I don't think it'd be an issue, but around town I'd probably want to die.
As for your flywheel concern I'm not 100% certain so maybe someone can correct me, but like MuhThugga, I also believe the LS2 GTO came with the LS1 flywheel. I recall someone with an LS2 GTO putting in an LS7 clutch kit and needing to buy an LS2 flywheel with it. Double check with someone more knowledgeable for sure, but don't let $100 stop you from buying it.