When you say - you "have" an upgrade - does that mean you have it in the box or on the car????????
HKS is a very reliable company with high quality components. I would suggest that you install the kit just as HKS suggests. Meaning that you take every step one at a time and you will be successful in the installation process.
If its already installed - then I would suggest leaving it as is. Any modification that hasn't been tested by engineers is a gamble and may lead to more money being spent for you to "become" the engineer - and design and test and redesign and retest. Certainly some people have the resources and time for such activities and some don't.
But if you are thinking of using only one turbo from the twin turbo setup then that is a mistake. Try going to a website called turbobygarret.com and research the right size and learn to "read" a compressor map before choosing a single turbo for your setup.
As I recall - the really cool aspect of the Supra twin turbo setup is that it uses a smaller turbo for the "get off the line" power and a larger turbo for the "topend" power. One shuts off and the larger on "kicks in" to take over.
Hope this helps - Happy motoring!!!!!!!
