cams are not that difficult to install, the hardest part is getting to the tensioner
luckily the tensioner in our cars is sping loaded, it just takes a bit of fancy manuevering to get to it and push on it
as for the turbo not getting what you pay for, thats not true
the stock wheel horsepower rating that most p5s put out is 98 whp, yes 98
when you jump to a stock turbo setup, with all stock piping...everything...you are looking to push around 140 whp
it may not seem like much, but for a car that puts out 98whp stock that is quite a jump from one mod alone
if you throw on turboback exhaust, hardpipes, and at least an upgraded sidemount (which in total naturally puts the car to about 8-9 psi, which is still safe on the stock motor) you will be seeing around 160-170 to the wheels
with the above setup on a tune and running the car at 10 psi (9 is what I would recommend, but plenty run 10 just fine) my last dyno had been 200 wheel torque and 185 wheel horsepower
if you plan for a certain hp range and stick to it, you will probably spend around 2000 to completely go turbo, for gains close to the 80hp range...if you just go with a stock turbo setup you wont get that much gain, but if you buy it and plan to run aftermarket parts from the moment you buy it you will cut a lot of losses and see pretty damn decent gains
as for cams:
the jdm cams are nice, however they are extremely hard to find...theres a few for sale on the forums right now, but thats a very rare sight...youll see gains of around 10-20 hp from cams, I think the last I heard the jdms put you at around 16 hp...twiggy sticks cams are very very nice, but they are impossible to find, even worse than the jdms....protege garage also sells integral cams, which I highly recommend, but they are costly
