So, I've grown up and bought a 5 series..

Hi guys, I got tired of my 2002 E46 320i and bought a 1999 523i manual (M52 single vanos) which were very well taken cared of and has only done 140 000km. I always wondered about these cars till I got into it and test drove it! I immediately fell in love with it, the first thing that impressed me was the build quality of the interior and the silky smooth gear action.

Also, it pulls like a train compared to the 320i I've had. I don't understand how they can have the same kw and almost the same torque..it feels way different to me and although it's a big car, it doesnt feel like it at all.

Things that I have noticed that needs attention:

Slight vibration from engine on cold start idle
Vibration and shudder on clutch. Clutch and dual mass flywheel needs to be replaced I guess.. (don't know if it's the flywheel that causes the vibration at idle?)
Slight hesitation between 1000-2000rpms

Things that I have done already:

Changed oil + oil filter
Changed air filter
Cleaned the MAF
Changed fuel filter and fuel pump
Removed the CDV
Fitted rear mud flaps, still waiting for the front one's to arrive from dealer.

I have noticed this car has got a cast iron block and not aluminium like the other 6 cyl's I've had. '96 328i and '02 320i. Can someone please explain why? Also, it doesnt appear to have a catalytic converter or a post lambda sensor, only the 2 pre lambda's on the exhaust manifolds..So, if I fit a performance exhaust in the future this won't throw any codes?

Here's some pics of the old girl