I have three of them and they all still work! They are/were amazing computers. Just buy a cheap one for your project and keep the parts. That way you can tell yourself that you could always restore it and you aren't destroying a good one.
Should someone come along and want the internal parts at a later date you can always sell them. It's not like we are talking about a rare Commodore edition 4000T where they only made 200 of them.
BTW what are you building? Will it require modifying the case? Is a regular PC motherboard going inside?
Jeff