Hay bugman welcome to the team.. I hope you enjoy your time here, this forum its filled with a bunch of extremely knowledgeable gentlemen, (Not me mind you!)

but most of the guys are great..
Moving on to your question, here is what I can take a swing at!.
Car - Hyper 7 (don’t have one) but I have heard great things about them.
Use - Racing (GET GOOD electronics!) Neu / MGM / 25 - 30C lipos..
Motor -To save weight go with the 1512 (try to find a "Y" series). More torque / less draw, will stay a little cooler.
MGM compro (great controller I have one and I love it!) to save some money and weight, but limit yourself to 4s try the 12012.
http://www.icare-rc.com/motor_contro...hless.htm#MGM2 (middle of the page) just where the Car and boat controllers start.
4s 30C should keep you very happy, that’s what the team racers use and a lot of guys here. A lot of guys also run the 5s, I use 5s on my 808 and it kickass ass! But it's really to much for the track that's why I just bought (2) Poly quest 4s 30C 4500mAH lipo's, remember you only have some much room inside your cavity before you run out of room and hit the bottom of your body. My total height limit is 45mm so I'm limited to 37mm height on my lipo choices after taking in considerations the height of the battery box and the strap holding down the battery.
I don’t have a clue what .21 v means, I but know that mine is faster then theirs

..
Have a great one...