Good choice moving from the Cressida to the E30. You will love them and are a lot more fun to drive from an enthusiast point of view. Maintenance wise, they are about the same but I will admit wholeheartedly, there is a bigger community for the E30s and parts are much more available than the Cressida, a dying breed of Toyotas. Be prepared to do some work on the E30 because you and I both know, they are old cars. Parts
can cost a little more. For a fair comparison, a Toyota OE oil filter - $5/$6 with discount. BMW OE oil filter - $10 with discount.
The numbers will add up but as long as you use OEM parts (purchased from the US, which I have been) these cars are indestructible. Bulletproof M20 inline-6 motors paired with a ZF auto or Getrag 5-speed transmission, both built to last. Automatic transmissions are just as common as manuals, but there is a big hungry market for manual cars. You'll find an automatic car no problem. Insurance wise, they're pretty cheap but always always always check with your insurance agent first for a better quote. Shouldn't cost any more or less than your Cressida. Working on them, you'll run into infamous German engineering and appreciate Japanese engineering but that's part of the deal when you pick up a BMW.
I have an E30 (I think you saw it that time I came to your house) but in general, check to see if the following have been done or not:
Mechanicals
-Timing Belt (well, all belts really)
-Waterpump and thermostat (highly neglected and should be replaced when t-belt is done)
-Radiator flush
-Transmission and differential fluids
-Guibo (sometimes called a flex disc) and centre support bearings (if manual)
-Shocks/springs (most have been blown and should be replaced with OEM or Bilsteins)
-Suspension bushings (whether replaced or not)
-Check the suspension for ball joints/tie rods, trailing arm bushings
-Shock mounts (highly neglected by some owners)
-Steering rack (90% of them out there are leaking anyway - not much you can do)
-Check for intake/exhaust leaks and ask for Aircare results
-If it has AC and it doesn't work, likely the R12 has leaked and 99% chance the expansion valve is shot (very common)
-Check whether owner has replaced the fuel pump in its lifetime
(This is all I can think of off the top of my head)
Body
-Check for rust in all wheel wells. I believe most E30s were galvanized from the factory. They're old cars so don't expect the paint to be perfect and/or surprised of accidents
-If a sunroof model, check to see that it can slide all the way open/close and if it can't tilt up and down.
-Look at the trunk and pull the carpet up to check for rust as much as possible, especially where the power antenna is
-Take the spare wheel out from the trunk and inspect for rust
-Check to see if the doors open and close properly.
-Check to see if the central locking (power lock system) works
-Check to see if all windows go up and down (if power windows)
-Transmission mounts (if replaced or not)
(That's all I can think of off the top of my head)
Electricals
-Make sure all lights work (headlights/foglights/turn signals/backup lights/interior lights/dash lights/console lights etc)
-Check to see if there are any DME/ECU codes stores (
Click - Lots of info here
-Ensure car starts up w/o hesitation when cold (to check for fuel injection problems etc)
-Check when alternator and starter were serviced
-Check and listen if all speakers work
(these cars typically do not have any major electrical issues unlike VWs and E36+ BMWs)
(all I can think of now)
This
website lists most common issues with the E30. Most of them should be taken care of and/or aren't a problem but I highly recommend buying a car that was well taken care of (like mine for example!)
Another good website/forum to ask E30 specific questions is R3VLimited.com (yes, that's a 3) and E30tech.com. When in doubt and you find one you like, I
highly recommend you bring the car in to a reputable BMW shop for a pre-purchase inspection (PPI). The PPI will save you a real headache and your wallet. Lots of shops specializing in these such as Nixon Automotive in Burnaby, The Euro Shop and German Auto Sports in Surrey, CG Motorsports in Richmond and of course, your typical BMW stealerships.
Parts: I buy them locally when the price is right from Autowest BMW but there are other independant shops here who have good pricing, otherwise, I buy from Pelican Parts (SoCal) BMA Autoparts, AutohausAZ.
Good luck in your search!