Single turbo?

I have seen poeple with twin turbo supras replace teh two turbos with one huge one. I was wondering if anyone with an RX-7 has done it and what did they think about it.

it's a hybird Turbo .... reduce turbo leak , fastest reaction .
Example Trust T78 (1.9Bar !)
http://www.r33skyline.com/Gallery/For_Sale1/Image_02.jpg

There is guy in town who deals with rotarys for a living. He just bought a third gen RX7. The first thing he did was replace the twin turbos with a single large turbo. He made major improvements to the exhaust at the same time. Horsepower is way up! I understand that the turbo lag is also more noticible. However, he is more concerned with straight line than autocross. It all depends on what you want your car to do.

on an FD the stock twins are best for applications where you need low end acceleration (autocross). The single larger turbo is better for things like drag racing.