Slam possible with Tubes instead of SS ??

Not with your speakers for any kind or reasonable cost probably I would think for teh reasons Tvad mentioned..

The speakers in my system are similar.

I've gotten excellent results overall including slam using the Bel Canto ref100m amps.

I go for clean, uncolored sound with good detail and excellent dynamics including slam.

I use a relatively inexpensive but good quality ARC tube pre-amplifier in my rig to very good effect.

I have experimented with both tube and SS DACs. This is another area that can be experimented with to getting a tubelike sound with little or no compromise in the dynamics including slam.

Solid state is capable of high output, hence volume. But, to me "slam" is more meaningful when one is talking about dynamics at reasonable volume levels. In that case, I think it is much harder to find solid state amps that sound dynamic and deliver "slam"--many sound lifeless and bloodless, particularly at lower volume.

Want to hear real dynamics? Try listening to an OTL amp (e.g., Joule, Atmasphere, but NOT the Tenor). If one is using extremely efficient speakers, one can hear a surprising level of "slam" from good SET amps pumping out less than 10 watts.

Are amps using KT88's and 6550's particularly good choices (all other things being equal...) for listeners seeking more "slam" (whatever that really is) than certain other configurations?

so, looks like I will stay the course for now. Still tweaking the room and speaker placement for best effect.
In the end I want it all, ie: slam, detail, musicality, warmth etc. and of course I want a deal on the gear. Others have done this right here in 'Gon Land. It could happen.....