Want some more advice...?

I'd go for the A4000T... anyday, anytime. Simply *the* Rolls Royce of Amigas. Best computer I've ever had. I still use it on a nearly daily basis.
I've had an A4000D, but sold it a couple of years ago. Once you get a CDROM cramped inside it, it's even tighter than the A3000.
I still have my old A3000, but I have to agree with the above that it's a real challenge to expand. The onboard SCSI-1 is dead slow so you would have to upgrade it anyway. Amber is nice, but in the end it's only ECS.