If I had a smallish amp, footprint of maybe roughly an A4/A3 sheet of paper, whereabouts would I be best off getting it placed to keep it out of the way of cargo/stealthy? I was thinking if I could have whoever installs mount it to the bottom of the parcel shelf. Is there a problem with that idea?

the parcel shef will be fine, i have both of my amps underneath the front seats. some people think that they will over heat, ive had my 4ch speaker amp under there for years and just recently upgraded my sub amp and never had a problem yet (touch wood lol). the passengers dont kick them because there mounted to the front where the rail is

I have a cheap amp under the passenger seat like that as well, never had an issue.

I had 2 amps upside down to the parcel shelf in my 2nd gen, had them spaced a bit though so there was air all around. They got hot, but never overheated. And the music was always loud.

the parcel shef will be fine, i have both of my amps underneath the front seats. some people think that they will over heat, ive had my 4ch speaker amp under there for years and just recently upgraded my sub amp and never had a problem yet (touch wood lol). the passengers dont kick them because there mounted to the front where the rail is

can't mount amps under the front seats in the Verada's as they've got foot vents for the rear.

my amp install isn't what you call stealth- they're mounted to the sides of the boot, but you could always fit a false wall (or a mesh wall) over them

+1 for under seats i have my 4 channel and mono under the front seats neat and tidy and more importantly out of the way and hidden,, (from the thevies)

Yeah but as hojo said, I can't do below seats. The passenger seat has a foot vent as well as the CD unit for my satellite navigation, and the driver seat has the foot vent only. Under the parcel shelf still sounds like the go.
I also don't want to bother with a false wall although I will if I have to.

If you had a sub, you could mount it onto the box at the back, so its out of view. That's what I've done with one of the amps...

Nah no sub just cabin speakers.

If you had a sub, you could mount it onto the box at the back, so its out of view. That's what I've done with one of the amps...

+1 this

its whats ive always done.

except with my first amp, had a small enough footprint so i put it on the back of the rear seats in the boot.

Firstly a small footprint isn't one the size of an A3 sheet of paper lol A4 is getting there. If it's a Class-D amp generally speaking the parcel shelf theory should be ok, although I'd pay particular attention to the cooling design of the amplifier, especially if you're considering mounting it upside down.

I also wouldn't go mounting it to the sub box. Aside from being bad for the amplifier, it's an absolute pain in the bum when you need the boot for more important things. Try to put it somewhere that's both safe and efficient for the amplifier, and practical enough to not impede on general use of the car. I personally favour the under-seat solution, but you're hindered by the rear floor vents if you consider them a higher priority (they're next to useless if you ask me).

Firstly a small footprint isn't one the size of an A3 sheet of paper lol A4 is getting there. If it's a Class-D amp generally speaking the parcel shelf theory should be ok, although I'd pay particular attention to the cooling design of the amplifier, especially if you're considering mounting it upside down.

I also wouldn't go mounting it to the sub box. Aside from being bad for the amplifier, it's an absolute pain in the bum when you need the boot for more important things. Try to put it somewhere that's both safe and efficient for the amplifier, and practical enough to not impede on general use of the car. I personally favour the under-seat solution, but you're hindered by the rear floor vents if you consider them a higher priority (they're next to useless if you ask me).

Yeah I have it on my desk, it is A4. The previous mounting holes used were on the bottom and it looks like it would dump most of its heat out of the sides and back which are heatsink fin designs. Even without the vents, as mentioned I have the motorised drivers seat and GPS unit under the passenger so that is 100% not an option. My two options are either mounted to the back of the rear seats or the parcel shelf. Will speak to the installer.