not one of my fave, the Kent is one of my fave.........but i would rather work with the GTT lump, and all i said was that its better than your 1.2.
and no, fittin and exhahust will not cause harm.....UNLESS its fitted badly and blowing, back pressure on a turbo is not theoretically needed, to take advantages of larger pressure differentials. BUT a tiny bit is needed to preserve the turbo as oil seals can leak and possibly fail altogether.
And as for high tech, most of the popular highly tunned engines are not very high tech...namely the crossflow, pinto, XE, Zetec, K series, A series, cosworths......all very basic engines.
a good engine should be the best power/$ ratio, rather than teh msot expensive and new design. The new F4R is a good engine, but not seeing much attention from tunners.
and what about the mechinical complexity of modern lumps, the harder its getting to tune them, if you want drivability, then a short duration 3.2ltr V6 is for you, oh but economy.....how about a 1ltr micra.......
Fact is, the GTT is a good engine.....which is why people dont change them for other engines....to get the same proportional increase in power, say 20%..how much would it cost on teh GTT lump and how much on yours.....