How much HP did you gain afteradding a CAI and what brand did you use?

Usually the manufacturer will say 7-9hp.
On the dyno chart that is 7-9hp more somewhere along the chart, not nessesarily at the peak. So, it usually turns of to be about 3hp at the peak.
There is usually some negative pressure resonance in the stock box that causes a dip in power. If they make sure there unit has a positive pressure resonance at that same RPM voila' 9hp increase at some artbitrary RPM.
Most CAI's perform about the same as others.

what CAI's are known to make that much power at the cars peak RPM

Iceman made the only true CAI for the first gen neon, but has now gone out of business. Only way to get one would be to find a used one. I often run across them for about $170-$180 shipped to your door, so let me know if you are interested.