gearing question

I'm going to be getting a B16a2 in the next week or so and the place where I will most likely get it from has a 4.785 final drive and a 4th and 5th gear from a gsr that they could install befor they ship it?
I'm deffinately going to do the final drive, but i'm wondering about how the 4th and 5th gear set will change the performance of they engine?

the two gears would run about $100 so i'm wondering if it is a worthwhile thing to have installed.

Also the motor is going to come with a Honda factory LSD, I'm pretty excited because right now i just have a d15 in my 92 LX

thanks all
Sean