I also use the Paramours. I've added a second pair of stock output transformers and beefed up the parafeed choke but these mods only cleaned up and tightened the bass, not really gave it more power. I usually listen to jazz and you are right, the combo does well with jazz. The other day I modified my Foreplay preamp which really did affect the bass power and output. I switched out the 2uF Hoveland output caps and replaced them with 4uF Auricaps. When I put on "The Yes Album" I was blown away by the power and authority in the bass! Now my system is really capable of full blown rocking out! And with the Paramours to boot! This is in a 11.5'x17.5' room. And the bass that was somewhat boomy is much better contained! This made for a top to bottom improvement with all frequencies in better balance.
If you preamp is cap coupled you might try upping the size and possibly quality. I am no EE type so you might speak to the preamp's designer about this.

Good luck!

G.