Thanks Nug and Mike, this is the kind of helpful info I was looking for - Someone has always done it or something similar. The G25-660 hits so hard for a small turbo, that's going to rip!
Clicked that link and found this straight away, and they are near me. Thanks so much.
I got my car stripped down ready for the half cage this weekend -
There's almost 60kg in the front seats.
Nearly 20 in the rear seats including all the seatbelt retractors and some very heavy sound deadener that sits under it.
Still have the carpets to come out.
The underbonnet sound mat was quiet heavy too, but I can't remember exactly what it weighed.
13kg in the spare wheel and jack assembly.