White smoke in the morning may not be a problem at all. It usually is condensation in the exaust pipe. The black smoke is that your running rich fuel in your car. Rem the 100kw was setup to run your standard fuel. Since you are driving around the suburban areas you start and stop alot. Only when you give it a decent thrash do you get enough pressure to push out the soot.
If you wanna get rid of it try this. Get some injector cleaner and go for a decent drive down the freeway for about 1/2 to an hour doing about 110km/h and you will find that the buildup will go away. It also seems to give you back abit of fuel economy back also. I've done this in the past and it worked every time. I just ook a trip to Newcastle and that blew out all the black soot.
I've got bigger problems my car only does like 260km on a full tank!(35ltr)