Is the X5 4.8is right for me...

[Hobbes]

Hello all. I'm currently considering an X5 4.8is as a replacement for my 2005 B6 Audi S4.

I recently acquired a commute (used to be 1 block, now it's 40 miles a day) for my new job, and I do not want to deal with a manual transmission in the Audi anymore. Sitting in gridlock inching up a hill for 2 hours sucks with a manual.

I've been looking at the 4.8is and it seems to fit the bill for what I'm looking for.

I haven't had a chance to drive the 4.8is, but the specs seem to point that it is pretty quick. I love the Audi's hustle and used to have an E39 M5 as well... so I do want something that can pass people with ease. Loud ass after market exhaust option is a plus!

My requirements are...

Quick/Torquey/Can hustle a bit
Decent sound system
Can carry a couple surfboards (shortboards) with or without a roof rack
Automatic (duh)
Light off road/camping capability

By light off road capability I mean dirt trails with small ruts or driving on the beach. I go camping/on trips a lot. Most of the places I go my friends Civics and Camrys can go, but they get stuck/have trouble. So its not like crazy "real" off road stuff.

My friend also told me to look at a Range Rover Sport Supercharged, but this car seems really large and I've heard many stories about Land Rover reliability issues. Porsche Cayenne also came into the picture, but I do not know much about Porsche in general.

I'm also leaning to BMW because I've owned two that were pretty reliable, and have a fantastic shop (Avus Autosport in Glendale, CA).

My main questions are

Is the 4.8is quick enough to be somewhat similar to my current Audi in terms of passing Prius drivers etc?

Is it fairly reliable compared to the other brands (Range Rover/Porsche etc)?

What is the deal with the adjustable suspension? If it is set low for city driving does it stay low? or is it a vehicle entry/exit type feature?

Sorry about the long post! Thanks in advance for any information you can provide!