Thinking about a speed run car

[NoControl]

Ok just wondering since I've been using some old nimh sticks on my tc5 but the area for the batterys have 2 peices of plastic that are screwed on and are basicly shaped to hold a custom "cell pack" like nimhs or a123's and since my nimhs are almost dead and I'm tired of the packs sliding around I was thinking a 3s3p would be nice , cuz it would fit perfectly, and it would be 9,9v and if I managed to get a MM 7700 I could "theoreticly" hit 100mph, but the fewest and least expensive cells on fleebay were 2300mah 10c, 8 for 68$ shipped.