good fun test riding 6's

the 7 I wanted to check out had been sold unfortunately

now I'm pretty much decided between 2 sixes.
both 1999 with 24k km's
one green with a nice muzzy pipe for 6500 but only 3000 trade in, so most likely to sell privately if i buy this one, unless I can talk him up to 3500 trade in. this one is me favorite
the other is a grey/black/bluey sort of paint scheme with stock pipe for 7000, but he offered 4000 for the trade in.
so both more expensive than I planned on spending when I started this exercise, but worth it I reckon for what I'll get.
not sure if i'll trade in the zzr or try to sell it privately (If anyone is interested in it feel free to pm me).
just wanted to ask a few questions to get the benefit of experience.
what sort of warranty should I expect to get ?
should I get the bike checked over by a third party. Is there anyone who offers this service? Like racv do for cars.
If so whats the best way to ask the dealer ? they might freak if you want to take it out for a day to get it looked over.
anything else I should know ?