There is several tools needed to tune a car like a wideband o2, egt gauge (exhaust gas temperature), and fuel pressure gauge. A wideband unit like the LM-1 unit is need to make sure the a/f ratio is not too rich or too lean. If the a/f ratio is richer too than the car will loose a good amount of power.  It is also not good to see a lean a/f ratio because it can cause detonation and high egt temperatures. It is necessary to have a egt gauge when tuning a car. It tells a person if they exhaust gases are too high caused by  lean condition, detonation, or too much timing or not enough. The pectel has control over the fuel pressure, so it is necessary to make sure the fuel pressure does not go too low or too high. You can actually see the duty of the fuel injectors go way up if the fuel pressure is too low. The increase of fuel pressure can reduce injector duty if it is too high. 

The pectel demo software can be downloaded from pectelusa website.  

Key points on tuning

1. Make sure fuel pressure should be at 42psi and it should never lower than 42psi, but should not go any higher than 60psi for most cars.
2. The a/f ratio should be 14.5:1 off of boost. The a/f ratio should be around 11.5 to 12:1 at wot with boost.
3. The egt temperature should never go above 1,500F for too long at wot. I make sure it is always below that.
4. It is good to take 1 to 1.5 degrees of timing out for every bound of boost. 
5. Read as much as possible on tuning. 

This is how I would recommend doing tuning, but there is always other ways. I would recommend going to a dyno shop after the initial tuning on the street. It also might be necessary for some people to seek help from a local shop with experience with tuning.