Your right on Sabrewings, although I don't think an L67 is a turd low end wise either, but i understand what your saying. The GTs i've drove felt nice and strong especially around town, my dad has a 2000 GT its bone stock but it feels peppy around town. I've enjoyed driving it what little I have.
With a GT and GTP stock and in good running order lining them up from the start the GT and GTP should be side by side depending who catches traction first and at around 35-40 mph the GTP will start to walk away. At least thats what I witnessed in the past anyway. Driver skills plays a big role too.
Let me tell ya, 3.29s and a 3,000 stall on a GTP makes a big difference on low end. Traction ain't happening without some sticky rubber! I only have basic stuff done too, imagine if I was cammed and headed? I couldn't imagine what 9.5 comp would do...