Posting this in both X300 and X308 forums. Currently 2003 XJ8 owner. Although it seems I’m always fixing something or chasing a code, I’m very happy with the XJ8 and it’s reliability. Don’t know much about X300 and assuming they are similar in many areas like reliability, ease to work on and part costs, correct? Any specific things to look at when inspecting. I’m out of town and found one a few miles away from where staying. Planning on looking at before head home. 132k miles

 

Parts for the SC X300 are getting a little harder to find. (seem to be many more X308 SC parts around)

 

I think the X300 XJR’s are definitely cool but, the electronics are the weak point in my opinion. The body control modules go bad, water ingress on the ECM, EGR issues and probably the worst thing to deal with is if the catalytic converters go bad, the aftermarket ones cause forever check engine lights unless you find a good used one which is probably like finding hens teeth nowadays. There’s a (SLCM?) module mounted on the inside of the left rear quarter panel that goes bad all the time as well. I almost bought a 97’ XJR about 6 years ago but the rust was a bit too much. Mechanically they’re great cars but, it’s a shame about the electrics. I drove one once and it had good power but the rest of the car was in sad shape. Just a few weeks ago we had an original owner of a 97’ come in with 60k original miles on it and it was beautiful. I didn’t have a chance to get a picture though.

 

308 has way more BPM, SLM failures and forgetten keys. other than that pretty much the same

biggest problem with those cars is they're slower than a sloth on xanax

 

My experience with the X300’s is that they have way more electrical issues than the X308’s. They’re also older and prone to have more mileage when they aren’t broken. I personally feel that they have really good pickup even for the naturally aspirated models.