Originally Posted by fanglemeister
No doubt turbocharging is the answer for overall power production, but on the downside:
They are harder to tune for good manners - for instance you have to size the thing properly, and you need to dial in a bunch of retard and fuel at low rpm to get the impeller to spool quickly or they suffer from turbo lag, which can be very frustrating when you need instant power and nothing happens for a second or three. In fact if you are very serious about the turbo project i recopmmend a standalone efi system vs. tuning it on the eec. Most aftermarket efi's support BIG low-imp injectors.
You have more, and bigger heat issues than with a blower or Nitrous - underhood heat, engine coolant and oil heat, just more heat, everywhere. Check out spark plug access on a turbo 5.0 Mustang.
There's more to it, but suffice to say just these two issues alone will add quite a bit of money to your project's budget above and beyond installing just the turbo hardware!