Rear mount and ns mount match up you just have to fabricate and OS mount, driveshafts should fit as the 5e/4e drops in the yaris bay and shafts fit so it's got to be the same the other way. If you do this I'll be keeping a keen eye. I've wanted to do this for ages but the cons outweigh the pros..... the yaris handles so much better than the starlet for a start. But you'll probably be the first to do it, have 105bhp out the bag and potenial for around 125bhp with a few mods. You can also turbo/supercharge the 1nzfe with off the shelf parts.