i was watching some japanese motor show and there were tuners that had set up their almost stock cars into drift/time attack cars .. meaning they only drifted when pushed hard but they were fully controlled drifts.. the only mods they did were adjustable coilovers, lsd, engine boost was increased. the s15 and rx7 with similar mods were eating the corners whether be it gripping or drifting,... the s2000 did look twitchy when pushed, but it was very quick gripping, even more so than the s15 and rx7... so the s2000 chassis strength shouldn't be a problem because of its X-bone thing and the fact it was quicker than the rx7/s15 when it was required while weighing pretty much the same as them.
i was also looking at a website containing pictures of an rx8 before and after it was prepared for drifting... HUGE chunks of the chassis were taken out to prepare it for drifting :S... doesn't that mean less chassis strength?? a roll cage was added but why make the chassis weaker in the first place ??