gasgas ec boy 50

[wence]

Hey guys,
Looking for a bike for my 3 yr old and came across a 2004 gg ec boy 50 for 1500 aud.
A couple of questions:
-what are they worth 2nd hand?
-any probs to specifically watch out for?
- are they fairly tall like a ktm or more like a Jr50(they look tall.)
- how fast are they and can they be limited?
- is it the same deal for parts as my gg300?

Thanks guys, any help will be appreciated.
We live in Australia by the way.
Cheers Mark