Who said that the passenger said wouldn't being coming out as well? Nah, it will stay in this time, purely because my g/f wants to do a few laps in the car with me. And when I say the interior being stripped, I mean seats, carpet, centre console, all interior plastics besides the door trims and dash, rear speakers and stereo. Basically anything I can remove, will be removed. I would take the door trims out too if it wasn't for the electric windows.
And the spare tyre will be removed while on the track as well.
By removing all this I would say that it would have to be up around 50kg. Thats a small person. I know that 1 extra person makes a HUGE difference in my car.
Then I will be looking at racing buckets that are MUCH lighter than the factory seats.

And also going to an Oddysey battery and removing that abortion they call inlet plumbing and making it a LOT shorter.
There is heaps you can do to reduce weight if you look hard enough without going to the ridiculous extreme of making the car unsafe by cutting holes in the bodywork etc.
I'm going to weigh all the stuff I take out so will let you know what weighs what and just how much I did take out.
I'm good at pulling things apart.
Darren