In addition to a few basic tools in my garage tool box, in my car I carry:

• an assortment of zip ties,
• a small roll of duct tape,
• a super glue brand name called Future Glue that seems to work on automotive plastics better than others,
• a small plastic tarp (4'x6')
• a small 9 LED flashlight w/fresh batteries
• my BMWCCA Member Directory (saved mine from when they published a hard copy booklet)

 

GearWrench offers a good set of 3/8-1/2" Torx drivers that can be had for around $25.

I'd also recommend getting a set of metric hex bits as well.

 

Autozone sells a $100 dollar tool set that I use, It includes both metric and standard, 1/2", 3/8", and 1/4" sockets 6 and 12 point. A 1/4' screw driver with various size bit tips including some torx sized. IMO its the best bet. and buy those torx sets mentioned above and needle nose pliers. a magnetic pick-up tool. and auto zone sells a set of 2, ratcheting combination wrenches 1 has sizes 14,15 and 17,19. and the other is 8,10 and 12,13. All these sizes in 2 wrenches. Oh and a big adjustable wrench is always handy. I recommend getting some 3/8" pivot for the 3/8" drive.

So basically
$100 - Great Neck tool kit w/ case. (see below)
$10 - Torx (star) wrench socket set for 3/8" ratchet (see below)
$10 - Allen (hex) wrench socket set for 3/8" ratchet (see below)
$30 - Duralast set of 2 combination ratcheting wrenches (see below)
$5 - 3/8" universal pivot joint. (see below)
$10 - adjustable wrench.
$5 - Magnetic pick up


$170 - for a decent tool set that gets the job done.

tool set ->>
http://www.autozone.com/autozone/acc...er=840851_0_0_

3/8" pivot --->>>
http://www.autozone.com/autozone/acc...er=534057_0_0_

allen bit set ---->
http://www.autozone.com/autozone/acc...ier=94663_0_0_

The combination wrenches are like these except its a set of 2 wrenches and each end has 2 sizes. So each wrench has 4 sizes. This one isn't bad but its $$ --->>>
http://www.autozone.com/autozone/acc...er=561038_0_0_

Star (torx) bit set ----> http://www.autozone.com/autozone/acc...er=704328_0_0_

 

www.harborfreight.com

Although they don't carry big name brand products pretty much everything they sell is warrantied AND a whole lot cheaper.

I've been buying all my tools exclusively off of them and haven't had a single problem yet.

 

I got this time ECS Tuning and I really like it

http://www.ecstuning.com/BMW-E92-M3-..._Tools/ES7176/