You'll take a massive hit on the depreciation of the car you already bought. Depending on the size of the deposit you put down, you may find you owe more on the car that it is worth, so you will have to put in more money on top of your car just to settle the finance.
If you put in a decent deposit, then you might as well have bought the 116i in the first place, gone to the bank and made a big cash withdrawl, then set fire to it.
Stick with your current car.
Or if you have GAP insurance, arrange an accident! lol
116i Sport 5 door Crimson Red 2012 -
120i M-Sport 3 Door Le Mans Blue 2009 - 2012