re: Brakes
If You track the car. you should learn more about pads and fluid. Your life depends on in.
DOT 5 is a silicone fluid spec and is generally not used anymore.... and definitely not good for a stock Elise/Exige.
Dot 4 or 5.1 is good. 5.1 is Castrol SRF and is a very good, very expensive fluid ($70/quart, like a good bottle of wine

). I highly recommend it. It is synthetic and works great. You would only need to change it once year.
You should be able to lock-up the brakes. If You cannot something is broken. Severe brake failure on the track is no fun at all... Get it fixed.
Generally rotors do not have much to do with stopping, unless the car vibrates i.e. uneven wear.
Check calipers (stuck), ABS (not working), masters, booster, etc... Fluid, if it is fresh and there are no leaks in the system should not be a problem. Check the fluid color, it should be clear. Have it flushed and bled properly.
My standard brake test is, with engine off:
1. Pump the pedal to get rid of the 'reserve' in the brake booster.
2. Press the pedal really, really hard. You should feel the flex of the lines and the rotors under pressure. You should be able to floor it. The pedal should not feel spongy or too easy to press. In a good brake system with no air and braided hoses and 'hard' pads, you would not be able to floor it.
3. Let go a little from (2), so the pedal comes off the floor, but still maintain a lot of pressure in the system, and keep your foot in the same spot. The pedal should just stay there with the resistance from the expanding hoses and compressed pads trying to push back. It should not move or give. It it kind of moves down under your foot, you have a problem.....
Finally, I do not know the track... 115mph to 40mph to turn in, should be 150' or so with stock brakes. I have Brembos, so 50 to 80' works for me. Braking force is important because it sets up the car for turn-in. Not enough brake and the car will not turn so good.
Anton
I have a race shop replace fluid once a year or every 6 track days with DOT 5 or something that hasn't had any fade issues. I did put on the RC5 pads after the last owner who tracked the car with stock pads, maybe my rotors are just bad?
I can lock up ABS on the streets because they are dirty and crappy but at a clean smooth race track it doesn't happen.
If anybody is familiar with Portland International Raceway I hit maybe 110-115 on the front straight and have to brake between 450-500' and I feel like I should be in the 350' range from what others have told me.