From where to where is the best

[jog5000]

.......... place to ground out the engine block? I want to add another grounding point on my engine block, to the chassis, but I need to know where the best points are.

Geez I seem to be doing a lot to my car, in order to solve one problem, and nothing has come up right yet

[Brianmoooore]

There are provisions for an engine mount to chassis rail earth strap on both sides of the car - but it won't solve your problem!
If an E30 needed two straps, then BMW would have fitted two. These are not cars built by accountants.
You are trying to solve the problem on your car by randomly replacing everything, rather by analysing the fault, testing, and deducing the cause. When you eventually find it, it will be something quite simple and , in retrospect, obvious.

[jog5000]

Problem is cost. To have something tested here usually costs more than the repair and the parts themselves. I figure replace parts. When the problem is solved, then I will know what caused it AND I will have new parts in my car.

[Brianmoooore]

Don't agree. An important part of fault finding is to determine the fault preferably without touching or distirbing the suspect part in any way. To do so risks the possibility of disturbing an already faulty connection or joint, resulting in the fault dissapearing, leaving you with a car that can fail again at any time and still not knowing what the fault was.
Conversely, by disturbing things that aren't faulty, you run the risk of disturbing connections etc., that are still functioning OK, but might not when reconnected with slightly different contact points. This introduces nre faults, which may a) replicate the original fault, b) mask the original fault, or c) worst of the lot, create a fault which has an opposite effect to the original fault, and give the impression of having cured the fault.

Get down to your local plumbers merchant and get a cheap pressure gauge and tee piece.