Need kit suggestion

Hi, I'm new here and I was wondering if a newbie like me can get some suggestions from you probies.
I am interested in buying a stock reprap kit and modifying it as a summer project to gain experience with 3D printers
I am looking for a kit that will mostly supply the specialized parts (like motor, extruder, belts, gears and etc). I will try to use the parts to create my own variant by building the frame, doing all the programming, and wiring (probably with Raspberry Pi board and java).
I have had some experience with designing models and running Stratasys 3D printers at a Polymer Company for a NASA's 3rd Frontier Project in Ohio.
All suggestions and explanations are appreciated!
Thank you

I think you'll have problems designing a new printer without having an existing one. One problem is getting printed parts printed for a new design.
Another is that lack of familiarity with 3D printing could result in design flaws that need quite a bit of work to correct. So I'd suggest building a proven design such as the Prusa i3 first.