The upper pipe is a no brainer, just cut it short enough for the new outlet location.
The lower pipe was the RRE pipes included in the turbo install kit (J and L pipe). I had no trouble using them as is to connect to the MKIV. I used a coupler over the 2.25 inch pipe though to bring out to the 2.5" of the stock Supra elbow. I used the 45 degree elbow on the bottom, and the 90 on the top. Worked beautifally. I also used the stock supra IC mounts to bolt it in place, To hell with metal strapping...
When I switched to my current tubo, I got the RRE "20g style 2g lower IC pipe" and it fits up in a similar fashion. The only fabbing/cutting I did was to fit the IC higher up in the car. One square hole where the stock IC outlet came through. I also modified the stock Supra shroud to work with the opening in the DSM bumber cover. Shrouding is key to that thing being at least worth its own weight in shit...