You can get an M135i for less than a GTI right now though. Enough to cover the first couple of tyre replacements anyway!
Really?
The best prices I could find were approx £22,700 for the GTI vs £26,500 for the M135i (both manual 3dr) 
Maybe you can get into a vanilla spec M135i cheaper than you can get into a GTI heavy on the options. I think most of the changers here had around £3k of options there on their GTI, maybe nothing (or very little on the M135i)?