Hello!

Ive been stuck with 282 Index points for a fair whilst now!

Ive been doing 4-5 races a night with 1st, 2nd and 3rds. aswell as lots of Personal records being set. But im not recieving more points?

Any thoughts?

You currently have 203 server points

Index points, or LFSEI so to speak, is something different;
general-server-questions-f7/what-is-ex-lfsei-t23.html

You can unlock other cars either with server points or more LFSEI. (Server points are faster in this case).

Now, i only drive LX4, will this effect the speed in which points are made?

That depends really on who else is driving in your class.

general-server-questions-f7/noooo-not-points-t17.html

Driving alone produces one point. Driving with 8+ cars can result in ten points (if you are good )

...and you get several so called "good lap points" when you are within a range above the actual WR.
Depending on track and car, a teammate of mine make something like 10 points additionally a race. Plus a win makes a total of 20 points a race...