As an owner of STrads who has pretty much acquired everything i own s/hand or trade-in, demo-unit, etc. here is my own philosophy on upgrading and on the Strads in particular:
1. The nice thing about a Strad is that it would be difficult (particularly given your quality electronics) to make it sound less than amazing by mere mortal standards. That is some serious speaker you are talking about, and there is a reason why many considered the Strad as belonging in the world's pantheon of great speakers.
i have not heard your electronics with the Strad...but can say i have heard the Strads with Krell, ARC, Gryphon, CJ, and a few other names...and in all cases, i heard good sound. some better than others of course, but in no case did i feel the sound was strident, or unappealing, or anything less than great "Sonus Faber family" sound.
2. Plus, few if any of us are going to upgrade "one more piece of equipment"...and be finished forever. So someday, if you choose to upgrade your electronics, you will now have a world class speaker that, as Paladin says, will have the ability to show off your new electronics.
3. It is yours ears and your wallet, so i am only sharing my own personal philosophy. But in general, if you love the STrad (and many people do, including me), i would be surprised if you regretted buying it.
Relative to the Cremonas which i know well and respect, the Strad will have a quality of refinement in your mid and treble...plus enormous bass.
4. As for future electronics/upgrades/perfecting the system integration with your Strads...again, there is no perfection...but while you are waiting for future potential upgrades...you will be enjoying one of the world's truly great speakers.
Good luck and please keep us posted!!