Good morning-

While your car may need valve seals, this will not eliminate oil on the exhaust, tail lights or underbody. That is an external oil leak- hopefully you got it with the front cover and camshaft seal... but it might well be a headgasket. It is routine with M103 and M104 engines. Wash the engine good and watch for where it leaks.
There are plenty ppl on the list whom have sucessfully R&R'd valve seals without the specality tool shown.
If you got to pull the head... I'd highly suggest having the valve guides inspected and valves ground(minimum).

Michael