New self-installed suspension = Ahhhhh . . .

With the exception of detailing (which I do obsessively), and checking pressures, depths and levels, my driveway labour is confined to swapping wheels twice a year and fiddling  about with this:

I'm too old for crawling about now.

Does your car have RFTs?

Harry - no RFTs for me - I don't like how they drive.  I use Conti DWS06s, because Colorado can have weather ranging from 3 feet of snow to 95+ degree days (Fahrenheit!).  While it's a great tire, it does not perform as well on dry pavement as something like a Michelin Pilot Super Sport, but then again, the PSS is not exactly competent in rain or snow . . .

I do it for enjoyment - I have a lot of fun working on whatever car(s) I have.  Managed to properly do a head gasket once - that was LONG!

For me, everyday cars got too complicated a long time ago. 

A great sense of achievement if you can do it. And plenty of money saved.

Nice job Bob! I wrench on mine too, saves a fortune as they get older and restores my enjoyment of them. I replaced the suspension and bushings in my old 330i a number of years back and swapped it to coilovers while I was at it, so I know the work you put in. My E39 M5 is approaching rebuild time, the rear suspension and subframe bushings on that old girl are going to be fun

How do you like the Bilstein HDs? I'm thinking of going in that direction for the M5. I want more damping, but nothing too hard core. That car is so effective at offering performance while being able to cruise comfortably that I don't want to ruin that balance.

The E39 Alpina B10 used a Bilstein  setup and it was fantastic. 

With an M5, I'd stay stock.  Fabulous car!

I like the HDs (or B6s).  They tighten up handling without giving up too much ride comfort - I drive 27 or so miles one way to work, so a balance between handling and comfort is important to me. 

Next up is the water pump/thermostat - oh joy.

Harry, good suggestion, I'll google the Alpina setup for ideas. If Bob likes the balance of the HDs, doesn't sound like I'll go too far wrong going down the Bilstein route if I don't get too crazy.

Bob, I was surprised at the cost of the water pumps on the newer bimmers! I figured they'd be more costly now that they're electric, but damn they're pricey! The E90 pump location looks pretty cramped too, now more of a "what else should I take care of while I'm in there" kind of deal. I changed the pump on my wife's old Z3 some years back, which was an e46 3.0 liter, and in comparison to what you've got, that was a cakewalk. It was $60 and I was done in less than an hour. Couldn't be more convenient and all accessed from the top.

Clemenza - Yep, the water pump on an E46 is a cakewalk.  When I figure out how to post pictures here I'll post a pic of the last E46 I had - or what was left of it after a head-on collision where both of us were going about 40 MPH.  As the police report noted, the impact was "substantial."  Indeed.  The E90 isn't TOO bad, even with all wheel drive.  The trick, insofar as there is one, is to remove the radiator, which is straightforward.  The pump and thermostat are $380 on Amazon (it's a Pierburg pump, which is OEM) and that's the least expensive I've seen it. 

The job that will hurt is the oil pan gasket, which requires dropping the front subframe.  Next year!

Nice post Bob.

I'm another proud, self-taught DIY mechanic. I drove just two cars since 1984 (a 1984 Pontiac Fiero and 1997 Honda CRV) and my only need for shop work was tires, alignments, AC recharges, and dealer recalls. The CRV transmission went out a few months ago and I replaced it with a well maintained 2008 Acura RDX Tech. On one hand a very intimidating jump in sophistication and technology for a DYI-er, but on the other hand a car that tells you when something needs attention, and what it is. So I've bought the pricey Acura shop manual and using that along with information found on the Acurazine forum am keeping everything on par at a fraction of the cost of a visit to a dealer or shop. Fingers crossed I don't get into any electronic componentry failure. That's where guess work comes in and the need for computer diagnostics comes into play, although local auto parts stores can offer free help with error messages.

If you have an E39 a water pump can be considered a consumable! I lost count.