I think the GX was closer to the Magnum in terms of actual speed, but I can't deny the GX does look more impressive(even moreso compared to the cutscene versions of the GL that had the guns pushed all the way to the ends of the wings, and a skinnier fuselage).
The GX was definitely heavier armed than the GL. However, it is nowhere near as heavy or slow as the Magnum. Good players who fly Magnums are either very good at playing Descent 3 or fine-tuning their controller sensitivities, although I suspect both.
I started off with the GL, and between it and the GX, the only real difference in specs that I note between both is the larger missile store of the GX. You can turn fast enough to face any attacker or pursuer in either the GX or GL, but when it comes to the Magnum, on default sensitivity/ramp settings, you can actually feel
just how ponderous it is.
The D3 Black Pyro is essentially a GX, in any case.
Not really. The front design of the Black Pyro is completely different from the GX. They may have the same rear fins, but they're not the same. The GX is slightly slower, recalling from my D2 experience, but the BP has less stopping power than the GX and is less versatile when its armaments are taken into consideration.
The GX will always make me feel like I'm flying an agile block of metal. The GL and BP, on the other hand, makes me feel like I'm flying a durable piece of cardboard.
By the way, here are some fan-made GXes:http://www.youtube.com/watch?v=gdLMV3BJ2k8http://www.youtube.com/watch?v=sQJ-oTzB5D4http://www.youtube.com/watch?v=E7f6bPW4_ZQ