I'm not an network engineer but todays wireless solutiona are far away better and cheaper than those "motorsport telemetry" solutions. You may just need some access point on your car =)
I am

- Well Systems & Networks Engineer...
Im also a licenced radio amateur
Problem is with that aerial you listed, Its a directional antenna, and the gain quoted is the forward gain of the antenna.. They are very likely to have a narrow range so if you are following the car and pointing it at it then you may be ok.
The other problem you have is that the ECU in your car doesn't use the TCP/IP protocol stack so you cannot route the packets - IE you cant plug the solaris into an access point and get an IP address and then just connect to it with a laptop plugged into another access point running in a "bridge" mode.
the only real option would be throw a pc in the footwell and then connect your ecu to this and then use RDP (remote Desktop) to connect to the session on the pc in the car.
David