As supplied in the kit, the Purosil adapter hoses tend to be a bit on the long side, such that the K&N filter would be positioned too far forward, thus preventing the headlight and hood from operating correctly.

The procedure is to trim length from the adapter hoses and cut half-moon bite-marks into them to allow them to push further up onto their mating pieces. The pictures show the shape and depth of the trimming needed. You will want to cut a little bit, then push the adapter onto their fitted parts to check for proper alignment.

The net result of all the trimming and cutting is a K&N filter that sits 2" further back than with the initially supplied parts (see finished assembly below).

Install MAF-manifold on Turbo
Installation is much easier if you remove the turbo coolant line coming out of the coolant tank.

Put the manifold-to-turbo adapter hose onto the manifold. Slide it on as far as it will go and line up the bite-marks. Then install the hose-clamp tightly to hold this piece on.

Next, make sure that the turbo-inlet location is clear. You may want to push the alternator cable over to the side for clearance. Some people have had to remove the plastic shroud behind the alternator to make more room, but that really isn't necessary.

Apply a light layer of engine oil or soapy water on the adapter piece that will go over the turbo-inlet. Place the second hose-clamp very, very loosely onto the adapter (orientation is crucial). Using the tubing arms coming off the manifold as leverage, gently wiggle the manifold and push the adapter onto the turbo-inlet.

Reach around the underside of the manifold adapter and verify that the adapter has been pushed all the way onto the turbo. Then tighten down the remaining hose clamp. Reinstall all vacumn lines and the turbo coolant line to the catch tank.

Place the MAF-sensor to MAF-manifold adapter onto the sensor. Rotate it such that the bite-mark lines up with the tube on the manifold and the connector plug is vertical.This allows for extra clearance with the intercooler pipe (important with larger intercooler pipes). Then install the hose clamp.

Push the sensor onto the manifold and loosely tighten the rear hose-clamp.

Filter Elbow & Rotation
Rotate the filter-elbow so that it will point downwards a bit.

Spray filter oil all over the K&N filter and loosely attach the hose clamp. Push the opening of the filter onto the elbow and push the tip down and slide the filter onto the elbow. You only need about 1/2" of the filter on the elbow to tighten the hose-clamp. Pushing the filter too far onto the elbow will have it sitting too high.

Rotate the elbow so that the back edge of the filter follows the contours of the coolant tank. You should have less than 1/4" clearance between the filter and the coolant tank when the filter is parallel to it. If you have more, remove the MAF-sensor and MAF-manifold and cut deeper bite-marks into the Purosil adapters.

The final assembly looks like these pictures. Notice that even with the filter positioned optimally, you'll still have some rubbing with the hood and headlight arm. Over time, the filter will get flattened on the bottom by the headlight arm. That should be OK as long as the filter isn't punctured somewhere.

The increased performance is well worth the headache of this install. In June2000 I dynoed my car with 290hp at the wheels (342hp-crank) with this MAF4 kit and Turbo2 at 12psi of boost!