Thanks for the suggestions everyone.

I have had the springs on for about 1 month now and have likely driven over 300 miles total, easily.

Junkman, nothing else. Just spring pads, springs and shocks. I kept everything (spring pad thickness etc) the same as whatever was on the car originally - hoping to maintain things but better. All other front end components were replaced 1 year ago.

I will check for spring settling tomorrow in the day light. There is a small chance that they didnt "seat" into the right spot; however I still suspect that my springs are just not right for my car. The "thump" may possibly be from metal on metal contact since the tie rods and lower control arm are at a fairly steep angle - which likely causes some kind of contact when going over bumps at certain speeds etc. Just my theory though.

FYI, all of the other front end suspension components are 1 year old. I replaced everything around this time last year with Lemforder or equivalent parts.

The engine mount theory is quite plausible since my car does "lope" a lot and I have had the same mounts for a couple of years now - through numerous suspension and other changes.

I will try to capture some wheel well footage tomorrow and hopefully be able to post. Fingers crossed.