hello, I am looking at an ECU tune in the near future and wanted to know if there are any recommended (preventative) maintenance items that should be taken care of before heading down this path, as this is the first vehicle for which I have considered a tune.

IMO, there are no preventative maintenance tasks that should be carried out in direct support of a tune. A tune isn't going to have an impact on anything from a regular maintenance perspective.

If the car is coming up on one of the regularly scheduled services that includes replacing the spark plugs, do that a week before or after the tune, not at the same time; if something goes wrong (as it did for me during a recent plug change) it might be difficult to sort out if the tune is corrupt or if something else that was done at the same time is responsible.

FWIW, my 2014 550 had approximately 30k miles on it when I installed a tune, with standard maintenance before and after at the scheduled age/mileage intervals.

appreciate the info! mine is around 32k, and I have to inspect the valve cover seals, cam magnets and sensors during my upcoming oil change, I plan on changing the spark plugs around 50k miles.

I didn't tune my S55 I had and I always regretted it. The only thing the tuner told me is to make sure my battery was good/new. Picked up 3 tenths and 3mph with a OE Tuning 91 tune, mostly because it raised the boost by around 3psi. I went from 12.8 at 109 to 12.5 at 112 0-60 from 4.7 to 4.4. Might even do better with a drag radial. I have a handheld too so I can put it back to stock for smog. I eventually plan on going with an e40 tune which should be a big jump in power, but right now this has been good enough, and it's nice and convenient to run 91 octane. As a side note, the mileage went kinda nuts. I went from 26-27mpg freeway to a solid 30mpg, so eventually the tune will pay for itself.