I agree with CAB and the quote at bottom Of course it depends on what you are trying to accomplish and what other equipment you have, as well as your technical comfort. For some, a vcr tape of a gage on their dash might be sufficient.
For just monitoring a street car, a gage is enough. It would be like another dash gage. Glance at them as you like or need. Video if you need. That said...
Wideband O2 (WBO2) sensors effectiveness as a measurement of Air Fuel Ratio (AFR) depends on the system they are attached to. Because of that, all of them can give false and entirely misleading reading in certain situations. Innovate's systems will often give an error code in such situations, which IMO is better than a false reading. Their system is also very responsive, so you can see a lot of detail.
Datalogging is just what you think. Traditionally in testing it was a seperate device that would record information from the sensors. The old analog way was on scolling paper that a little pen moved up and down. The digital way usually involves very quickly checking each input channel and record it into memory. How fast is needed depends on whether you are trying to see each pulse down the exhaust on a very quick 1/4 mile car or a more general trend getting on the highway.
* Innovate's LM1, LM2 for example incorporate both the datalogging function and the WBO2 operation into a single unit. However the LM1 did not log additional channels without a second auxilery device.
* Inputs. In addition to the WBO2, on the drag strip an rpm input is very helpful. RPM usually just needs an input hookup that can recognize pulses. For tuning the carb on the street or non-straightline competion, both a manifold air pressure (MAP - vacuum for most of us) and a throttle position sensor (TPS) are very helpful. Having just one is still a big help. So having the option for two more input channels on the datalogger would be good if that's of interest.
I've mentioned Innovate here because I've used their stuff. My experience with their loggers is that they are consumer grade packaging and pricing on an engineering product. It's not a plug and play, super easy to use. The older logger (LM1) works best with a computer that has a serial port. But the version of software that works best needs something newer than Win98 SE. Issues with the LM2 seem to be solved and seems like you may not need auxilery units to log the rpm etc.
Over on the Racingfuelsystems forum, you'll notice racepack and innovate logs seem to be the most commonly posted and discussed. I'd check out those manufactures websites as well as FAST before deciding.
PS. The reason TPS and MAP is useful in tuning is in figuring out which carb circuit is working under non WOT conditions. Say the car is at 3000 rpm and coasting, its idle circuit, wheras 2000 rpm on a hill might be 35% throttle and onto the mains. But without the MAP or TPS, its hard to know exactly what was going in when you look at the AFR log. By testing and keep good records, you can figure out what is going on but those two devices make it much easier.
Quote:
Unless you want to try watching the gage rather than the road, or try hooking up a GoPro, or have a passenger with you while gathering data, get a unit with the ability to record.
And RPM data is also a near-must. Then your data needs to be on some kind of graph in order to make sense. So just having an A/F ratio line on a spread sheet is not much help. You will need the ability to manipulate the fuel line and coordinate it with RPM.
If you don't already have a data logger, do yourself a favor and get a wide band with RPM AND data record abilities. Believe me, after a day of tuning, making multiple changes and having multiple charts, the ability to have them organized in a comprehensive set of charts and the ability to toggle between them is invaluable.
I use an LM-1. Has Innovate worked through the initial issues that plagued the LM-2? If so, then that is the unit that I would recommend.
. Also, since I don't have a lap top. I have to wait till I get home to view the run on my desk top. I'm living in the dark ages when it comes to electronics ( still use the vehicle frame as a ground ). 
For sure the way to go. I actually have a roll bar mount for my camera that sets it far enough back to allow me to capture the tach, boost gage, and AF gage all at the same time. Still a long ways from a data logger, but a far sight ( pardon the pun )better than trying to monitor multiple readings while going down the track. No problems with my LM-2 so far.
I sold the Duster several years ago so I don't have a real need for it right now, I'm going to see if I can use someone elses laptop to load the Innovate software on and hook the unit up to one of my other cars and see if it will work in the other car. If not I will probally try and trade it in, if Innovate will still do that 
I bought a FAST unit way back when they first came out to use on dyno testing, it was a dual unit and quit working on one side after about 5 minutes of use the first time. Comp warrenty it but it stil wouldn't record and playback where I could see it and understand it on that screen 
and hope for more info....
