there is heaps to gain there ! but very expensive! the quads are expensive. i have been told, cams, headwork etc on the late model nissan motors (new skool) is very expensive, also depends on what aftermarket brands you want to use too

even just going to a after market computer will give you some noticable power gains.

In the end better off getting a low kilometer Sr20det and dropping that in, be cheaper than doing all those mods to a sr20de, but to have a really worked Sr20de would be awsome too! if you have the $$$ to spend