For R250k I don't think you will be able to find a DCT, as it will have to be a 2010+.
I get around 8.6L/100km on the highway doing mostly 128km/h. Town driving is anything from 12 - 13 for my morning commute. The first 3/4 of my morning commute can see me at less than 10, but then the hills and traffic lights start.
I have a manual 2008 135i (bought in 2012) and love the car. I did find less than perfect roads to be a bit less comfortable than I expected from a BMW though.
I keep repeating this in almost every thread, so people must be getting tired of this. Extending your MP by time is relatively cheap (R11k-ish for a year). Add 15 000km with your 1 year and the quote climbs to R38k. Keep that in mind when doing shopping if you want to have an MP for as long as possible.
I also found that tyres are expensive as expected. The rear tyres also don't last nearly as long as I hoped

Torque is addictive.
Other than the HPFP issues early in its life the car seems reliable, both from personal experience and the research I did before I bought it.
The battery cable was part of a recall, so you should be able to get it replaced whether under MP or not.
If the HPFP fails outside of MP it should cost you around R10k. That's what the warranty claim was when mine was replaced.
Since I've had the car only a vacuum hose was replaced which was not part of the service.