How reliable is it?
A common misconception about turbo charging the KL V6 engine is that its unreliable. This is mostly brought up by hearsay. Done correctly, it can actually be more reliable than a stock KL V6.
How so? The most common problem with these engines is the ignition. The distributor has a design flaw that causes the igniter inside to overheat and fail.
Following this guide, you will be eliminating the distributor for a reliable wasted spark ignition system.
The next common failure point is the timing belt tensioner, over time these lose pressure causing the belt to lose tension and eventually the belt slips causing a no start condition.
Following this guide, you will be using a manual tensioner that cannot fail.
For reliability problems, those are really the worst of it.
How much does it cost?
This is really about goals and your budget.
On the low side, someone with experience could do a bare bones basic turbo setup for little as $1500
On average, expect to pay $2500- 4000 for a quality setup that will be reliable, practical and powerful.
What's the weakest link?
This would be the connecting rods. The connecting rods on these engines are not very strong, it is generally speculated that they can hold up to 300-350hp. Around this level and beyond the connecting rods are subject to start bending.
How well will the power hold?
The transmission on these cars was not designed for racing or high power. They are designed around economy cruising. 3rd gear is most known to self destruct with increased power. However, 3rd gear and self destruct with aggressive driving on stock power. Saving this gear is mostly achieved with how power is transitioned into the gear. Such as, power shifting(not letting off the accelerator during the shift) is such a harsh shock load to the gear it can literally shred it.
Using a flat shift system eliminates this shock load by transitioning the power smoothly. It doesn't feel like changing a gear, rather a continuation of the previous gear.
