The TwEECer is the most poweful tuning tool available. You can literally control every aspect fo your car with a laptop. BUT, you have to take some time with it. The learning curve is extremely steep and patience / study is required.
But once you figure it out you'll be able to custom tune your car for whatever you want. I only have good stories to tell, I find that if you take the time to research the TwEECer and how it works then you'll only have positive experiences with it. If you're looking for something a little simpler and less powerful, but easier to use, then get an AFM PMS system.
In 6 days of really sitting down with it, I have already made 4 different tunes: A theft tune, IE car doesnt start unless you know where the TwEECer switch is. An everyday tune to run off 87 octain, a nitrous tune which retards timing and runs on 94 octain, and a NA tune which boosts timing and runs on 94 octain.
That question is like which muffler is best. It depends on the person doing it. If u like controlling it yourself than a tweecer,pms, etc is for you. If u arent into it, then just get a chip. Or if u plan on switching combos, u will have to pay for a re-tune again, but then again, if u dont tune it the first time, chances are u wont tune it the second time with the tweecer.
A note or two from a long time user....a search will give you much more.
A few bugs in the software here and there. Since it came out a few years ago there has been IIRC V1.18, V1.20, and the latest V1.30
The datalogging in V1.30 has some funkyness to it that will cause, every now and then, a data event or two to be way outta bounds from all values before and after. This causes you to have to find those inaccurate data events and delete them before you can have the datalog analyzed by other programs.
That being said, I did not jump on the V1.30 upgrade band waggon as I refuse to go through all that stuff before I can use Excell, EECAnalyzer, LogAnalyst, etc to analyze my datalogs.
There is a default playback feature for looking at the data events in your datalogs but I find it to be ... well ... kinda Mickey Mouse and I have rarely used it.
The Tweecer software itself is not anything that most peeps could not figure out how to use in a hour or two as the main things you do with it are:
down/up load info between laptop & pcm
change values in a table
change a value like idle rpm and such
datalog or capture data to hard drive for later research
The program itself is pretty self explanatory.
The most difficult part of self tuning is knowing why you would want to make a change in the values that Ford placed in the pcm. This requires some basic knowledge of how the pcm works.
The Tweecer is nothing more than a device that gives you access to the pcm to make changes and gather data.
For me, in spite of the buggy software, I've been able to tune my car to a level that has gone beyond my expectations.
If you have enough mods to need to get a tune for your car, it's a great tool, as long as you are the type of person that would like to dig in and figure out how it works, versus just paying someone to make it right. Would you build an engine, or pay someone? Same thing, I think...
Dennis