Definitely sounds like an interesting car. You may want to have a mechanic give you a second opinion on its mechanical condition since so much has been modified (just so you know it will be reliable). As for the rust: are you using it as a daily driver? If so, why would you really want a completely rust free 02 anyways? The rough north eastern climate will not be kind to such a car if its out of the garage regularly. If the 318/2002 is truly solid structurally and you are happy with its appearanc I say go for it. Just enjoy it, but don't bother restoring it.