Try compturbo, they made me a approx gt3076 sized turbo, triple ceramic ball bearing, billet compressor wheel, spools about 3500rpm, final tune not done so it might be a bit later once the ignition values are finalised. Supercharged cars are great, I wouldn't bother with twin charging. The toyota chargers are tiny, they might get you from 1000-3500rpm slightly quicker but then you will need some complicated plumbing to bypass it all together after that point. It is very hard to get a supercharger belt without cutting the car frame also. You could use the accessory belt but obviously this isn't designed for the sort of power you need to transfer to a supercharger. Twin charging is usually very expensive, very complicated and rarely successfully pulled off. I would just shift into a lower gear personally.