I dont think anyone is being negative, certainly from my point of view, I was trying to hint that taking advice from those that have the experience, Andy for example, and others who have already been down the road you are choosing may be advantageous to you. As mentioned by myself and others, I would ask Andy's advice FIRST, before deciding on any spec of engine and turbo/fueling combination. Experienced mappers see these cars day in day out and see/feel the results so are best placed to comment on compatability of components. From prsonal experience I have been round Kames in a car with a "large" turbo and it was comical.
I agree changing the turbo and remapping accordingly is no big deal but it will be an expensive learning process at around £2k+ once you take into account the cost of purchasing a new turbo, gaskets, fluids and a remap and the depreciation should you decide to sell the GT35 which will have a much more limited market than a GT30. In my opinion you should be trying this the other way round i.e GT30 first and if it doesnt provide what you want move up to the 35 and sell the 30.
The one comment I would totally disagree with is your assertion that you will use rev management to get the best from a 35. Depending where you are going to use this car i.e which roads/tracks you may find it very difficult to keep the revs within the required power band.
As mentioned good luck with the build and hope it goes well.