wow sounds like u got a fair few things wrong fella.tappy noise is prob the imrc (inlet manifold runner control) butterflies are chattering as they are only plastic and wear quite alot.

the speedo and cluster sounds pretty major but maybe due to the imrc as sometimes the plastic guide that opens the imrc snaps off.that can cause light to come on

rattly exhaust is common on the st170.normally either the upper and lower heat shield on the catalytic converter rusty n snapped or the bracket that holds the cat has snapped off too

clutch pedal sticking could be the clutch master cylinder seal sticking

hope these little things helps