I tried them on my JBL ti2k and like you say the bass got a little tighter, but also leaner, and the mids and highs got a little harsher... I ended up sending them back and going to carbon fiber speaker spike floor pucks on top of high duro sorbothane rounds from Amazon for $100 all in and got a much better result than the $550 isoacoustics...
I say hard pass on isoacoustics, on my components I have Ganymede Isolation bearings which are absolutely amazing, but they are no longer made.