(http://media.il.edmunds-media.com/bmw/5-series/ns/bmw_5-series_f34_ns_51211_196.jpg)
An aero body kit, suspension upgrades, new wheels and tires, plus interior accents are part of Hamann's 5 Series Touring package. Hamann offers a choice of 20- and 21-inch alloy rims. A suspension lowering kit drops ride height by 1.4 inches.
Source: Hamann Tweaks the BMW 5 Series Wagon (http://www.insideline.com:80/bmw/5-series/hamann-tweaks-the-bmw-5-series-wagon.html)
Hamann BMW salesmen have quotas to meet. That is why you want to shop at the end of the month. The sales staff will want to sell you a Hamann BMW to meet their goals. That will put you in a better negotiating position.
http://www.westcoastmotorsport.com/hamann.htm