Ive lost count of the GTRs using 044's without problems.
Being external doesn't mean anything in this instance.
There is a DIY on these forums about it, have a search.
You'll probably get one for $230 delivered, they're renowned around the world to be a good pump, and easily do enough flow for when you rebuild your engine later on (and of course will do your current target), so I don't see why you'd bother with denso. 044's are available from sau forum sponsors very easily. I have a feeling denso are used in supras-I'll find out soon enough when upgrading mine