This entry has actually been in the offing for a couple of months, but I've avoided posting it simply because (a) I'm not a big fan of "modding for the sake of modding," and (b) it takes time for me to work through the details.  Here's a rundown of the things that are likely to eventually "make the cut" on my personal mod list:

BMW HOMELINK  TRANSMITTER (OEM)

I'm not certain why this wasn't standard equipment on the car to begin with, but if you own a M3, you should probably have a garage to protect it in.  If you have a garage, you should probably have an automatic garage door opener.  If you have an automatic garage door opener, it should probably be capable of interacting with the Homelink system.   (I'm currently two for three, as I've yet to determine if my 20 year old German garage door opener is compatible with Homelink system .)  In any event, this is one mod that is really more a question of "when" than "if."  

ROYAL F1 SMG PADDLES (AFTERMARKET)

This has come up once before.  I've been aware of these SMG shift paddles for several months, but couldn't rationalize spending $300 on what essentially amounted to an experiment.  My assessment was that these were likely a good idea, but the price of admission was far too steep.  Then, about five weeks ago, the product designers contacted me and asked me if I might be willing to try out a set for review purposes here on the blog.  Following a few days of discussion, I agreed, and made the switch.  I'm not quite ready to post the full results yet, but let's just say that the preliminary results have been encouraging.

E60 M5 SMG III SHIFTER (OEM)

I'm not especially serious about this yet, but the boys at M3 Forum have been working on getting the zone illumination on the OEM M5/M6 gear shifter to function with the M3, and if (or when) they actually succeed in doing this, it is going to be an increasingly difficult thing to resist.  For now, it remains just a good idea; albeit a rather costly ($200+) good idea.

SUSPENSION IMPROVEMENTS (AFTERMARKET)

I'd rather not elaborate too much on what I am -- or am not -- considering here, but let's just say that I am toying with the idea of migrating to a coilover system at some point.  I continue to struggle with this decision, as I'm not sure that the payoff will be worth the hassle and expense, but the lure continues to be there.  For now, this remains a "someday" consideration, rather than an imminent upgrade, but the research continues.  Were I not of the opinion that the stock suspension is already rather well-tuned for most applications, all of this might take on a greater measure of urgency.  For now, I watch and wait.

CSL/ZCP FRONT BRAKE UPGRADE (OEM)

This is a much easier call to make.  When my present brake components reach the point where replacement is warranted, it is a virtual certainty that I will be migrating to the larger front rotors originally developed for the CSL (Note: the caliper carriers must also be changed).  It is an extremely simple upgrade, completely OEM, and delivers readily measurable results -- all for a price that is comparable to what you'll pay for the standard Euro market components (which I presently use to great advantage).  It is likely only a matter of time before I undertake this installation job, and I wouldn't hesitate to recommend it to any M3 owner.

FRONT SEAT WIDTH ADJUSTMENT (OEM)

If you're like me, you've found the M3 seat just slightly (and unnaturally) on the wide side for serious track work.  While it's true that some of this can be overcome with a proper seating position and seat belt adjustment techniques, the fact remains that the car could probably benefit from a more narrowly-bolstered seat.  Now, I know what you're thinking: "Chief, why didn't you just get the width-adjustment option when you ordered your car?"  The answer may surprise you, but having migrated from manual seats in my earlier M5, I really wanted to stick with those same manual adjustments on the M3.  That meant no power seats, and consequently, no possibility of factory width-adjustment.  Of course, it is technically possible to retrofit the factory width-adjustment system into a manual seat, but I'm after something a bit less complex, more custom, and likely more durable.  The CSL's OEM Recaro seat provides some adjustability by means of optional sizing pads, and my current thinking involves incorporating something similar into the stock seat.  In other words, I'm talking about pulling the seat back tray off, and carefully inserting some additional bolstering material into the existing frame.  Some have done this in the past for lumbar support, and properly executed, I see no reason why the same technique couldn't be used to achieve a truly custom fit width-wise.  I'll keep you posted ...

So, what's on your list of essential mods?  If you've found something that seems like an obvious omission from this list, why not drop me a line (here, or via e-mail) to weigh in with your opinion.  Who knows?  Maybe your suggestions will ultimately make their way onto my list, as well.