I would say buy, and look for the parts you need at your local junkyard, and fix the light yourself. Also find another shop to fix that timing chain, you shold not spend any where near a grand, with parts.
The click noise is most likely noisy lifters (a very, very common problem on these cars) and this is easy to adjust yourself. I'd buy the damn thing if you know what you're doing with a wrench, I can guarantee you that my 240 was in worse shape, and I LOVE the car. I view a slightly problematic car as an opportunity to learn. Also, if you're serious about a swap, you are going to have to commit to a large expenditure, and you won't have a car in the meantime. If I were you, I'd buy the car, then invest in a Geo Metro and not insure the 240SX until it's a done project. And yes, move to a state with no emissions laws. Minnesota, Land of 10,000 Lakes!