When deciding on a power train which should you go for? I will admit to being a little biased towards turbos. Here is my take on Turbo Engines.
The sheer exhileration and excitement you get as the turbo kicks in is something that sticks with you for a long time.
I will concede that due to lag the turbo does not produce much power low down. Even the mighty Mitusbishi EVO suffers from terrible lag low down in the power range. Instead of this getting you down view it as a car with a split personality. In heavy traffic it is civil and economical but if you are overtaking or enjoying a thrash there is a monster waiting to be unleashed.
Nearly all turbo engines are built to withstand more pressure in the combustion process. Most cars with turbos (yes even diesels) can be remapped to release loads more power. A remap is a simple reprogram of the cars computer which controls the wastegate, fuelling and thereby the amount of fuel/air that can be burnt. A remap will cost a few hundred pounds but will typically give another 30% of reliable power to your car.
After this modification there are loads more, if you strip down the engine and get it gas flowed and ported, strengthen the rods,pistons and crank and get it balanced you can look at doubling the power output of the engine. (Some cars can cope with 100% more power without an extensive rebuild although reliability may suffer.
A turbo upgrade will also yield substantial power gains, so look out for an OEM (standard case with uprated internals) or after market (bigger housing requiring minor modifications to the cars exhaust, wastegate and air intake housing diameters.) A ball bearing turbo will spool up quicker. Smaller turbos reduce the problem with lag. A twin turbo setup with a boost controller will control the sheer power and manage the delivery to a more progressive level again minimising lag. Large turbo conversions will make bigger power figures but tend to suffer more from lag at the lower end of the rev range.