How Low?? - Advice

[JJP123]

Basically should be collecting my 2007 318 D ES very shortly.. i can not cope with the standard 15" wheel and therefore i will be looking to replace with either 17 or 18" bbs lm's.

I was also going to go for 30mm lowering springs on standard stocks to give a improved stance.. just wondering if 17s and 30mm drop will be ok?

any pictures of different heights on different " wheels etc, would be greatly appreciated.

Thanks.