Dude I honestly dont have a clue of what you are trying to say man. Doing any kind of upgrades to an economy engine like the r18 will not yield as many gains compared to a k20. However you are very wrong when you said that its better to turbo an r18 than a r20, an r20 is essentially the same as a r18 only with a bigger displacement due to the stroke, they are the same engine in every other aspect. The r20 having a larger displacement will yield a larger gain compared to an r18 assuming we have the same turbo setup. Turbo does not increase oil compression, but I think you meant oil pressure. could you elaborate on what you meant by this? Vtec engine can be turboed there are some pros and cons of turboing a vtec engine, it all depends on what your goals are. Theres a couple of threads on honda tech and other websites regarding this subject. The r18 and r20 have vtec, however is not the high lift vtec that a k20 has, its a econo-vtec, temple of vtec asia has a good article explaning this. Both engines can take advantage of a turbo again it all depends on what your goals are.