The 128k/512k to Mac Plus upgrade was quite popular at the time. Sadly, it turned the computer into a Mac Plus, so the upgrade has (to my mind) completely negated any value of the computer as a collectable. It's not even a good, clean, original Mac Plus. In fact, the only original bits are probably the front of the case, the CRT and the brightness knob.

Rasmus: at some stage in it's life, the Mac would have almost certainly had the power/sweep board "repaired" (replaced under Apple's exchange program). A Mac Plus used solidly for 8 years would be very unlikely to have escaped power supply problems.