That would be most of us. Don't buy a no name brand from ebay.
It's one thing to buy a bent steel tube with no moving parts from ebay, but a turbo is an extremely high-precision machine that spins in excess of 20,000 rpms in incredibly tight tolerances and must be as close to perfectly balanced as possible. Turbo is not a good part to cheap out on.
Get your VF40 rebuilt. VF40 -> VF46 is not really much of an upgrade. Some reliability upgrade and a minor power improvement, but most folks that go to the trouble to swap a turbo go at least to a VF52, though I understand you don't really have a lot of the supporting parts.
Start thinking about that a bit. You would be much better off with a rebuilt VF40, a catless uppipe, a nice high-flow catted downpipe and tune than you would be with stock full exhaust with a still catted uppipe and an "upgraded" el cheapo no-name ebay crap turbo that's going to end up restricted by your stock exhaust anyway.
And if you truly think it's your turbo on the way out, you should really (really) stop driving the car. Replacing an unblown turbo is miles and miles (and miles) better than replacing one that has already blown. See the turbo failure wiki sticky right at the top of the turbo section. You do not want a blown turbo if you can avoid it. It has the potential to destroy the entire engine.
Also note, if you go from VF40 -> VF46, you are gonna need a new tune. Honestly, if you are gonna get a VF40 rebuilt with upgraded compressor and turbine wheels, you should get a retune. If you buy a new VF40 or have one rebuilt to oem specs, you probably don't need a new tune (though it still wouldn't be a bad idea).
Good luck!