HRS2 with a SW pod will help to make the car run well. You might want to try a Piranha motor with gearing somewhere around 12:34, maybe a little taller if the car will take it. I'd start with no added weight and add weight if you need better/different handling. True your tires carefully and get them smooth and well-broken in before you mail off the car. Easy to drive usually wins out over super-fast in proxy racing. The key is often times a combination of good brakes (so that the drivers don't enter the turns too fast) and good traction (so that they don't break traction and get a lot of chatter coming out of the turns).
Allan