Akai S1000 / S1100 samplers

Hiyas!

I have used an s900 for a few years... drums are great and I just got 
an s1000 w/ 18megs, the digital I/O and a acsi card. Where can I learn 
how to add an internal hard drive? Or a zip drive? 

Is memory for my baby still available? I did  agoogle search and for 
the price of 16 megs I could buy 3 more s1000s like mine. :-) I paid 
$150 and it's in great shape - does that seem like a good deal?

thanks!

Kiira