Ok, so here's some more detail on what i've found this afternoon, for those who aren't assured that "bolt on" really is as simple as all that....... (i'm always a skeptic on these things!)
Machining the I.D of the STi disc to 60.6mm gives ample clearance for fitment over the hub spigot, without excess play.
As in the post above, the step in the e-brake drum surface doesn't interfere with the e-brake shoe - there is 6mm clearance
In the picture below of the stock disc, there is a rubber plug offset between two of the wheel studs. This gives access to the e-brake shoe adjuster. If you don't drill a matching hole in your STi disc, then you have no means of adjusting the position of the shoes.
This is the adjuster underneath:
The dust shield can remain, there is room to push it back far enough to clear the Sti disc. BUT - there may be contact between the dust shield and upper balljoint at certain points of the suspension travel. Check this on your car, it may be preferable to cut away the dust shield instead.
For the brake line, it would be ideal to maintain the downward angle from the caliper, rather than coming out perpendicular from it. In this pic, the suspension is at full droop (albeit with coilovers), as the suspension compresses, you'd have a fair working angle on the fitting at the caliper if it were straight - I'll be going for a 45 degree banjo fitting, and having a bow in the line as it is with the stock caliper.
The backing plate for the e-brake hardware has a pressed lip - you can see it in this pic below, i've marked it with a pink posca pen (though it appears white). On my car, this fouls the disc (as mytmk3 found also on his - see further pic below). Not enough to bind, I can still turn the rotor by hand with it torqued down, but it would make a hell of a noise until it self-clearanced. Will probably have to shave this down a mm or so.
Here you can see (in pink marker), the section of the disc that contacts the backing plate. I wouldn't machine it as it is part of the structure of the disc (the cooling vanes)
and just finally, this lip you see protruding above the rear of the disc surface looks like it would be a problem, but its not
It actually clears that lip on the backing plate perfectly. [EDIT] this is incorrect, it actually does foul on the e-brake backing plate when you torque down the disc. It can be machined down 1mm though to clear.
Hope this helps some of you that want to know the potential hurdles before fitting your "bolt on" BBK
Cheers
Phil
[EDIT] Just a reminder guys, these notes apply to RDA branded discs, other manufacturer's might have slight variations on dimensions for non-critical surfaces. i.e: you won't necessarily have the same clearance issues.
