My car seems to be showing some slight vibrations at around 2000-2300 rpms range, you can feel it on the gas pedal and possibly hear something although it may just be a sensation from the vibration itself.

When you are below 2000 rpms it is fine, when you exceed 2300 rpms fine as well.

I feel as if it could be somehow related to gear change, previous owner had torque converter replaced, maybe something was done wrong?

Thanks for any input.

Sounds more like an dirty injector problem, run a couple of tanks with injector cleaner and see if it improves.  There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
Fiat 500x 1.4 multiair Lounge 2015
2010 LR D4 Commercial 2.7 TDV6

Will try and report back! Thank you!

I had the same thing, the vibration was very slight , but definitely there around 2000rpm.. The vibration pretty much disappeared after I had the transmission mega flushed, and completely disappeared when I changed the diff oils.. Maybe something to look into.. How many miles has yours done, and has it had a transmission fluid change..