Sorry for the delay - I was accidentally keeping an eye on the wrong forum (1st gen.) so I missed these questions. Oops!
Is it plug and play and much larger than stock?
It is plug and play, and very much so larger than stock (slightly over 50% more core volume to be sure at 20.5 x 4.5 x 9).
Good deal.
But these aftermarket intercoolers should be larger or deeper to be useful correct?
Not necessarily. Now, in simple terms larger is generally better for intercoolers, but as I recently responded in a PM there's three facets to an intercooler (not in order): your end tanks: computer-aided and cast is generally better to facilitate air flow in and out of the unit - you'll find cast end tanks on all the major manufacturers, your size: again, larger is generally better but you're restrained by size in front of the bay and how much modding you want to do to fit your unit - not to mention diminishing returns as units larger than stock replacement are more expensive, and the most overlooked, which is quality of the core: you want a balance between density (fins packed together) and size to facilitate airflow - you also want it to be staggered for better cooling. Bottom line, it's an equation of all three.
Our value proposition is simple: proven 40+ degree reduction (data on the product page), minimal difficulty of installation, and we try to give the best support possible. And we're a state-side outfit out of Miami.
Hope this helps!