Welcome... The 4000 has plenty of upgrades about, some easy to do/get some harder to find..
first think cd-rom > very easy. ide cdrom set as slave on second connector of ide cable to harddisk, download idefix97 demo from aminet.net and install it, away you go with cd access.. Idefix is a demo but its the easiest way i found of getting a cd working under os 3.
Check your battery is not leaking on the 4000, most common fault is it leaks and kills the clock and / or the simm slots.