I think the new f30 has made some great changes over the e90! Firstly the temperature gauge is finally back, so you can see when the engine has properly warmed up. BMW has now added a tire repair kit in the boot which is a good addition but I still think the run flats are sh%t. I have 17's on the f30 (Run Flats) and 18's on the e90 (Non Runflat), both arn't sport suspension and in this set up I would still say the e90 is a smoother drive than the f30. The overall quality in the f30 is amazing and in my opinion alot better than the e90 with everything looking alot nicer aswel. I have the e90 in a 6 speed manual and the f30 in steptronic! Must say i am very very impressed with the pull from the f30. Got great power to it compared to the e90, e90 is 2007 model so is the 115kw and 330nm version ( Reason f30 pulls alot harder) That's why I am considering remapping, but still abit stuck on which company to go to. With regards to the exhaust I never really noticed much smoke coming from the e90 and there isnt much coming from the f30 either, the one thing I must say about the f30 exhaust is that is sounds absolutely brilliant, much better than the e90.If you have any other questions just let me know. Sorry that the review isnt the greatest, just having a bit of a busy day today.