From what I understand about sequential gear sets they don't necessarily mean you can hold higher power levels unless you have them made for it. Its mainly for quick shifting, and if you think the R154s are getting scarce then putting a sequential gear set in your R154 will make it even tougher to service it if parts do break.
I think its the PPG company who has videos out there of them driving a Nissan S chassis with one of their gear sets, it does drive normal just noisy. I talked to a guy in Malta who had a sequential gear set in his R154, unfortunately it popped after only a few runs down the drag strip so he didnt get much seat time with it to tell how it was. He had a built 7M in the car.
I think the better option would be adapting a legit sequential gearbox to your engine of choice, but with that sort of investment you could probably buy and build 5 R154s and have them sitting on the shelf for when you need them.
