What is outrageously fast and an ARF.
I sounds like you need a Whiplash Mark.
You're right about the Magnum... it does look rather cheap the way it comes.
About the tracking in turns: I had a problem with that too. It appears the slot for the vertical stabiliser was out of line ever so slightly. It didn't show up when I was measuring it while putting the plane together, but it showed up during the first flights. Everything needs to be 110% straight at these speeds! I solved it by cutting a trim surface out of the vertical stabiliser, putting a couple of horns and kwiklinks on and trimming the plane.
I had to trim almost next to nothing, but still, the plane flies much better now.
In your first post you said you wanted to keep the ARF cost to a reasonable minimum. If 320$ is a reasonable minimum to you, then get the Whip... I suspect it is the best money can buy if you want something fast and sturdy. And it looks great with one of the airbrush motives.