^^ your link is a bit dated, so I'll add some things. First off, the rules are written such that if it doesn't say you can do it, you can't. Street Mod still requires a significant amount of interior.
-Steering wheel and steering wheel mounted air bag can be replaced as given in the street prepared rules
-Front seats are per street prepared rules
-Rear seats can be removed, along with any associated hardware and restraints
-Air bags, speakers, stereos, and similar accessories can be removed, as long as the resulting holes have a cover
-Interior rearview mirror and sun visors can be removed per street prepared rules
-Dash, trim, ceiling liner, carpet, console, hvac controls, steering column, door cards, and sound deadening, all have to remain intact
-You can make small modifications to make upgrades work, i.e. slight mods to a console for raised shifter, or cutting trim to fit a harness bar, etc.
If you have a hatch, I say the rear carpet and top cover is ok to pull out since it isn’t physically attached to the floor in the OEM configuration. Don’t forget to update/backdate to a center console without an armrest and get some manual doors and windows :D
Parking Lot Hero
2008 WRX daily driver
2003 ZX3 23D Autox Car 42 FSP
"Hella Functional - Raced, Not Hard Parked"