I know there are pressure gauges out there that will tell you what the back pressure is for a cat converter - it's screwed in where the upstream O2 sensor goes and if the pressure is below a certain pressure (real low like under 4 psi if I recall correctly) then the cat is not clogged. You might check with an O'Reilly, Advance or AutoZone parts store to see if they have one in their loaner tool program.
For ground integrity, I would think that a decent digital multi meter would be most helpful there. You could either measure voltage drop or resistance.
For the starter, the best way is to measure current draw while it's cranking. Another way is to measure the battery voltage while cranking. Using a known, good, fully charged battery of adequate capacity, if the voltage drops way below say 9 Volts (do not quote me on this) the starter should be considered suspect.
For ground integrity, I would think that a decent digital multi meter would be most helpful there. You could either measure voltage drop or resistance.
For the starter, the best way is to measure current draw while it's cranking. Another way is to measure the battery voltage while cranking. Using a known, good, fully charged battery of adequate capacity, if the voltage drops way below say 9 Volts (do not quote me on this) the starter should be considered suspect.