Flash space so I can put larger programs on it. But would RAM increase proccesing speed?
You cannot increase the program storage space!
It's a common thought for a newbie to think a lot is required, but a microcontroller is not like a PC, where the graphics makes the programs very large. Just 1kB can hold a lot of program in a controller.
More RAM (up to a point) in a PC will speed things up (depending on your usage pattern) since it's faster to keep data in RAM than to fetch code/data from a HD.
In a microcontroller however, adding RAM won't help, since you cannot add to the stack space or scratchpad memory.
You can use RAM (whether flash based or not) as data storage space, if you want to collect a lot of data eg. for logging every move a robot makes for later study, but that's an entirely different story.
Just use the project as designed for now and build up some experience. That way you may get to a point where you will be able to modify such parameters in a sensible way, but for now, you are best served by using the standard configuration, which has proven itself usefull for a number of first timers.