The 9000's are ok mate, pretty bomb proof but in my opinion far more barge like to drive than the 900's...

As said above IF you can find a 9000 CS Aero [they only made them up to 97 iirc?], they're 225 bhp and the one to go for! It's also the same engine they put in the later 9-3's in the HOT Viggen models [always makes me think of some shit Swedish porn ]

The Low Pressure Turbo 2.3's in the 9000's [170 ish] are obviously a bit better on fuel but the Full Pressure ones are obviously quicker [200-205 they did a few versions ]

I personally prefer the 900's though as mentioned before, less power but a bit easier to live with and parts are CERTAINLY cheaper and more freely available [body parts and interior parts] as there's more on the road still.

If you're asking what to go for though, the 9000's generally come with a better trim [normally find them with leather] and can certainly surprise a few cars on the road!

They're BOTH 4 cylinder mate and not much to choose between just depends on what you want when you try them

If you're looking at the older cars [up to 97] you can get some silly fucking bargains nowadays too