I'd get the GVP 060 accelerator from Software Hut if still available. Instead of worrying with SCSI and hard drives, I'd get a Deneb and boot and operate the machine from USB memory stick. That's what I've done with my 2000 and 3000 because I got tired of old SCSI drives failing on me. Will do the same with my 4000 as soon as I get my motherboard problems sorted there.
The newly manufactured Spectrum RTG boards from Software Hut should also be considered. I just got one for my 3000. My 2000 has an old Toaster card and a Personal Animation Recorder board in it, so I may skip the RTG route on this old workhorse of a beast. Definitely look at the Indivision ECS board so you can use modern, flicker-free monitors. I got this because my old 1084 monitors were failing quicker than my old SCSI hard drives.
The Mini Megi Chip thingie from AmigaKit should also be worthwhile. I have an older solution that does the same thing (gives 2 megs of chip ram).