Cool. What are the upgrades?
That's cool too. I just have the regular SST (4B SST Pro) though. I'm wondering if it's enough amp to drive the 4344's.
Yup, they're not cheap, but think of what any of the JBL 43XX pro series systems would cost new today, if they still made them. Big dollars, no doubt.
Upgrade-wise, they are worthy of a capacitor replacement throughout, or even a conversion to charge coupling as used in the MKII version. Either is not simple, but well worth the effort if you have the skills.
Some folks like to aquaplas the HF diaphragms, or changeout the drivers to the later titanium verions too. I exchanged my HF drivers to TAD berylliam to good effect.
A 4B would be a great match. If you want the best performance, biamping is the way to go. On my 4345's, I use a 2BSST/2 on the top and a 4BSST/2 on the bottom.