the best place to see whats available is kyosho's mini-z time website
http://www.mini-z.jp/modules/catalog/
you can also go to iwaver's website for vague pictures i guess but not much else there
http://iwaver.com/
just like you see the arguements regarding the mini-z vs. xmods, on
www.mini-zracer.com you also see mini-z vs. iwaver threads.
it boils down to iwaver making a cheaper product. and no matter how nice you may hear or think it is, it's cheaper for a reason. while it is undoubtabley a great buy for the money, it, just like xmods are no mini-z killers no matter what you hear or read.
the tried and true mini-z mr-02 is by far the best chassis to get for a mini-z racer. if your leaning towrd an iwaver you could try their cheaper verson of the mr-02 or wait a bit for their new 02 chassis which is rather different but unproven and if you go by iwavers track record for the current releases, it's unlikely the first batch will be error free.
i would hihgly reccomend atleast considering the iwaver though. the new 02 looks very intersting to say the least but with their move to sh&$% great planes for distribution the cost savings you normally achieve with an iwaver is much less an issue.
best advice to give, browse the forums, read up on them and make an educated decision or atleast an educated guess.