hot sparks ignition

[1970 merc admirer]

I have a Hot Sparks ignition in a 1970 280se mercedes.The problem that
i am having is >14.5 volts to the ignition,even though there is a new Beru
voltage regulator and 1.4 ohm ballast resistor which is placed between the coil
and distributor.The coil is a BOSCH blue with 3.3 ohm primary.The coils resistance was tested.
Do i need a BOSCH voltage regulator.?Iam willing to go that route if it
is the solution.The BOSCH regulators are 10 times more expensive.
Also of note,the engine is running rough and i suspect it may be related.
Would greatly appreciate any help with this problem.
Best regards .
Garth.