Interesting thread, I like it.
What was the outcome of this? Did you go ahead and get tubular wishbones?
if so, where from? Were they the USRT ones you were looking at?
I currently run a very similar setup to you and I'm also looking to go to the next level in terms of handling, I've recently bought some adjustable top mounts to increase camber and castor, as well as a shim kit for the rear end to add some more neg camber and dial out some of the horrid toe in these cars suffer with as standard.
i'd be very interested to see how you've got on, do you have a build thread anywhere?