Excellent choices. Either would impress your clients. However, a good pre-owned 7-series will eat up all of your 40 grand, or more. I would recommend a pre-owned 5-series. My wife owns a 2001 525iA, and it is a tight, solid vehicle, with one of the best rides imaginable. Check out this 525i in NM.
I noticed there was an error in the ad I linked to in my previous post (msg #66). The ad state there is no ABS in the BMW 525I, which is nonsense. BMW refers to their 'ABS' as 'DBS' (Dynamic Brake Control), which might have been the cause of confusion to the ad guy. The BMW 525 will stop on a dime. The 525 also has 'All Season Traction' control which gives the 'slipping' wheel more traction; and it has 'Dynamic Stability Control', a remarkable system that will help prevent sliding on slick surfaces. It is a very safe vehicle.