The first race I started near the back and that was pretty much where I stayed. At the start of the race the car was behaving a bit strange and then I spotted that I hadn't turned the traction control off

We changed the front tyres from 16" to 17" for the second race which i know lowers the revs a little so would probably make it bog down a little more but they were a lower profile tyre so thought I might get less tyre roll and be able to carry more speed though the bends. That didn't really work but the car did handle a little better and I finished 7th.
For the third race we put 17" wheels on the back to try and get a bit more grip on the back as it was breaking away and I'm sure some of it was because of the tyres rolling. On the front we put some 15" wheels to try and increase the revs a little to see if it would up the revs enough to stop it bogging down so much. It took the first few laps to scrub the tyres a little and get the feel of the car but then it all started to come together and I started catching the front pack and finished 4th.
It was a good day and we learned a bit more about getting the car on the pace. We have found that the front needs the 15" wheels and tyres on to get the revs about right so its almost hitting the redline along the straight and pulls well out of the bends. It also seems to want a lower profile tyre on the rear which is why I used the 17's which were wider and lower profile but the back still breaks away as you touch the brakes but is quite controllable.
Heres some videos from each race
Race 1 https://youtu.be/3Uj8cVoxxVA
Race 2 https://youtu.be/S_pyAwCKN_s
Race 3 https://youtu.be/YzvJtpmqXZ4