The purpose of this modification is to reduce wheel hop and torque steer by using equal length axle half shafts. This used to be a very popular modification for FWD DSM's. It actually does not require many parts. Just an understanding of its purpose and how everything fits together compared to the normal front-wheel-drive axle configuration.
The intermediate shaft has two bolts that hold it to the block. The missing bolt in the first picture (left of the other bolt) goes through the A/C mount, a spacer, and then into the firewall side of the engine block. The other bolt has a mounting point on the engine block just for it.
Looking at the first picture, the right hand side of the intermediate shaft goes into the drivers side of the transmission (where the stock "long" axle would have gone.) The left side snaps into the drivers side AWD axle.
On DSMs a Chrysler axle seal spacer was required for this modification. Apparently this part is no longer available. But after test fitting the axles into the Sonata KM177 transmission, it seems that I do not need the seal spacer on this transmission.
Notice the mounting bolt in this first picture of the intermediate shaft. There is a hole jut to the left of it for a second mounting bolt. These bolts have the same part number (Mitsubishi: MB297860.) There is a washer part number listed for these bolts too (Mitsubishi: MF450406.) The only difference between the two bolts is that the missing one in the picture also needs a spacer if you do not have air-conditioning. The spacer goes between the intermediate shaft mount and the engine block (Mitsubishi: MB297732)
The axle looks like it has already been replaced. The old one has a driveshaft/axle company label on it.
7/1/2004 - I just read that Fidanza is making 30% stronger than stock axles for the Eclipse. 4340 chrome-moly outer joint with a high-tensile steel shaft, rugged yellow CV boots, and high-pressure synthetic grease to keep them lubricated. So there are other options out there.
1G '90-92 DSM FWD Equal-Length Halfshaft Install FAQ & Instructions