The spoiler is bolted on and yes if you take it off there will be holes left in the deck lid.
how do i remove rear spoiler on rx330 2004 model for repainting or recoating clear coat
To remove the rear spoiler on a Lexus RX 300, first, open the rear hatch and locate the mounting screws or bolts that secure the spoiler to the vehicle. Carefully remove these fasteners using the appropriate tools, usually a socket or screwdriver. Once the screws are removed, gently pull the spoiler away from the hatch, being cautious of any adhesive or wiring connected to the brake light. Finally, clean any residue left on the hatch after removing the spoiler.
Just unscrew the mounting bolts on both sides and tape up mid tail light wires. You can fill the holes in many ways.
Remove rear seat, them remove rear deck to get to the speakers.
The 2013 Scion xD has 50.7 in. of rear shoulder room.
The 2013 Scion iQ has 33.8 in. of rear hip room.
The 2011 Scion tC has 52.1 in. of rear shoulder room.
The 2014 Scion iQ has 35.9 in. of rear head room.
The 2014 Scion xB has 41.2 in. of rear head room.
The 2014 Scion tC has 52.1 in. of rear shoulder room.
The 2010 Scion xB has 38.0 in. of rear leg room.