All cars are going to be a little diffeent and depending on the mods you will get diffrent results. I had some serious mods done by Eurochared but all fairly simple and on top.
CAI, Injectors, cat Back Deletes.

I went from 156 RWHP to 192.5 RWHP. That is a 23% gain.

I have seen some NA's without any mods reach 174 -175 RWHP.

But Horse Power is only part of performance enhancement. Changing your shift points, raising the Rev limiter, these things can improve the way the car drives. So, if you like aggressive have them make changes for that.

You will be pleased.
For the record, my car is amazing. It is on fire.

roadster with a stick