The Macbilt sump has extra capacity - 6.5 litres up from 4.5 litres. Also has inverted wiiiiiiiiiiiiings to keep oil low, and hinged access to trap oil in pickup area. If I'm lucky there is a really poor photo of it here.
+1 on All Bumper Repairs. They have repaired my plastic front lip 4(!) times.
Also recommend most highly Porirua Motor Body Repairs. Have used them for more times than above and always done a great job.
So... you measure the disc to see if they're 294mm or 270ish ie 4 pot or 2 pot (assume 4 pot for 98 STI), then head down to BNT and tell them you want a pair of (2 or 4) pot Subaru STI front discs. It is that easy.
When you get the discs you measure diameter to be sure, and count the holes - 5 holes at 100PCD.
That's all you need.
I won't be going anymore. My son has got his birthday activities over the weekend and attendance is required.
Uphold the honour of Subaru, Loren and Trev.
In the words of Babe the Pig - Su Baa Roo - to your car be true.