as I use my bugeye for carting half a ton of carp fishing gear around the country I keep removing the rear seats to make space ( I know I should have gone for a wagon )

I have removed the rear seats, space saver wheel etc, and the car does feel different weather this is to do with the extra noise from the exhaust / fuel pump etc

my question is how much weight would I need to remove from my bugeye before it made any real difference and how would this be done

if any thing this will stop my mates leaving macdonalds wrappers in the back seat

2 weeks ago I had half my fishing gear nicked and Im weighting on the insurance to tell me weather its covered or not So with all this extra time on my hands I have started to play which is normally a bad idea