Lowering your car is not practical at all. Do it for the looks, depending where you live, you will have to drive slow to avoid rubbing/scraping due to road imperfections.
Personally, due to the potholes, cracks, bumps, construction etc around my campus, I do not think I will lower my car anytime soon. I have scraped many times already even with the stock sport suspension.
2007 E90 328i - Titanium Metallic l 19" VMR V710 l H&R Trak+ Spacers l M-Sport Rear Bumper l Mtech Rear Lip Spoiler l Hamann Front Lip l Eibach Sportline l AA N52 Signature Exhaust l OEM Blacklines l MTEC V3 AE l 6000K HID l Nokya 7000K Fogs l MTEC License Plate LED l Interior LED l 15% Tint l BlackVue DR380G-HD + PMP