Quoted from mollyspub:
Now I'm getting confused ... I can just convert the spring and it's now the same? No need to buy the pinball life kit?
The only difference between early 90s style mechs like funhouse has and the later style is that early use a conical compression spring and the later style uses an extension spring. The extension spring requires extra bits to mount it to, but you already seem to have those in your pic (the plate sticking out of the crank, and the holes on the EOS mounting bracket).
The other differences between the older and newer units are that they use a normally open EOS (without capacitor) and a taller coil stop, but you need the normally closed EOS and capacitor to work with funhouse since it doesn't have a fliptronics board, and you'd want to keep the same coil stop so that the flipper still acts the same as before