****** spacers! You lot would put them on even if the wheels were already outside the wheelarch. My car is wider than yours therefore I'm better mentality. Madness!!
Geometrically it is utterly mad to f**k with the suspension and steering settings without good reason. Good looks (arguable) is not good reason. It could even make a car dangerous. Adding condoms must in all honesty have been a bit of a warning sign!!
On the rear it is just about accetable to add a spacer. OK on multi link etc I may even reserve that judgement, but overall 15mm per side shoudn't affect the compression arc too much, even if it doesn't hit the £38,000 paintwork!
On the front you could be destroying a set up. 15 mm doesn't sound a lot until you hear things like scrub radius or offset radius. Offset radius can be negative or positive by just a few mm. Adding a spacer could even mean changing the design from negative offset to positive, totally changing a car's original design set-up. Power steering might hide a bit of the feel but it will totally screw with the handling. A couple of mm may tidy things up and make it feel sporty but 15mm?? More like f**k things up especially with DIY fitting and looks-alone mentality. So it might look good in Lidl car park but start the engine and you might be driving a kit car. Possibly an ill thought out, even dangerous kit car.
Spacers are for when you've bought aftermarket wheels with the wrong offset. That's it.
Why? Just why would you?
Welcome bro. 
You not go for the 12.5? 
Only happened under serious load though? 
