Essentially, if your not going for large numbers, or a build to support it get the split second AFC. The reason i recommend that over the AEM is cause the AFC has more support here. Support is very important if you are new to tuning. The AFC's base map is pretty good to. I havent messed with the AEM unit but i know its not as common so if you hit a snag and need help, it might leave you down for a bit (same with haltech). AEM and Haltec both make great units, so im not putting them down but as i said, the support just isnt there (on here, for free).
Basically, what these fuel controller units do, is take the incoming signal from your stock ECU, and then it modifies it and sends the corrected signal out to the engine and its components (injectors). So you technically highjack the ecu and put in your own numbers. The nice thing about the AFC, AEM, and Haltec units is you can change these values yourself. With the Unichip you have to pay each time you tune it, and that will happen quite often if you dont have all the parts you want yet.
Its not hard to tune IF you have a basic understanding of how it works and move in small increments. The hardest part of tuning is coming up with the base map (the map which basically allows the car to run close to stock). Since its already in the AFC, the hard part is done. Now you just make logs of runs, monitor the air fuel ratios, and see where it needs to be adjusted. This is done via a grid (called fuel table) in the split second software. you adjust the numbers up and down to get the correct air fuel ratio for your setup.
Im not going to lie, its not someing you want to just put in anything and see how it goes, you can definately do some damage. If you make small changes, do it slow, you will be ok. I highly recomend a boost gauge, and a wideband 02 gauge before you start any tuning. The AFC's base map is pretty good and you should be safe but dont change any numbers till you can see what your doing.
