You're quite welcome.

Hmm, I wonder how universal those sensors are. I'm thinking adding tire pressure indication to vehicles that have no tire monitoring system or only a rudimentary one on wheels that may or may not have original provisions for a sensor. Be nice to do quick checks on vehicles in storage, too. If they're HUF, then they may not be that physically "universal." I think I'm ordering the TS401 anyway, though.

Here is the sensor with the programming device.
Autel TPMS Sensor Maxitpms Pad Programming Accessory Device MX Sensor 433MHz | eBay
Talking about retrofits, looks like that the X5 TPMS controller is pretty simple and doesnt require any additional equipment except the sensors. It is pretty cheap too. The only problem will be to "extract"/display the information.

I'm looking at just adding sensors and then using the TS401 to get pressures.

That would work. I will be getting the programming device anyway so if you need sensors programmed I can do it for you.

Seems like this is the best place to ask about the correct sensor for a MY 2010 10/2009 production E70. I understand there are two different sensors in use and they "changed" in 2010. I've got a set of winter tires with senders from a 2012 E70. I have not tried them yet with my 2010, but my expectation is they won't work. What is the correct sensor for me to install in these? I found these on Amazon - are they "the ones?" http://smile.amazon.com/dp/B00HEEXIKO

smile.amazon.com/dp/B00HEEXIKO

Search the part numbers on realoem.com and you will find the compatibility. If i were you, I would install 1 wheel, reset the system and see if it is going to work. All OEM tire sizes have the same outside diameter, so one different [OEM] wheel/tire will not damage anything or trigger the DSC.

Just got my TS401 and it is an awesome bit of kit. If I could get sensors that were compatible with all my wheels it would make taking routine pressures much quicker.

Look at MX-Sensor from Autel. I got a set, but I am still waiting for the programmer.
TS401 is a great tool, even more so considering the price i got it for ($99).

So will this actually work?

Most TPMS sensors do not report until they are in motion. Do the TPMS tools have the ability to wake up sensors that are in standby mode?

One another note for anyone getting any of the Autel TPMS tools, post some feedback about what tool you purchased and what you think about it overall.

Seems the TM601 is actually cheaper than the TM501. I like the option for keyfob testing in the 501/601 if it actually works.

There are different types of sensors that wake-up by rotation or pressure change. The Autel tool can wake them up easy.