my friend is planning to buy an Unser next year, and due to the fact that the original 1.8 engine is a fuel guzzler and very underpowered for a car of this size, he is planning to change the engine, maybe a 1G supercharge or turbocharge....has anyone here done this conversion before? any problems with it? he's not going for 1JZ because this car is used for daily driving and it's function is a family car, so no need so much power, and partly because of the road tax is too expensive. please share your views and comments, thank you