The extra block is just an additional support for the hot end and the bowden connector.

Autoleveling is the "patch fix" for a badly calibrated printer.

I assume you have Marlin firmware running on an Arduino like 90% of the rep rap community? You need to become familiar with three calibration settings:

Max Z Height - The absolute printing height of your printer. Your printer "homes" to Z-Max and has no Z-Min endstops. This means that it can't find the floor, it simply finds the "ceiling" and uses the Z Max height to locate the floor. People often confuse their Z-Probe as Z-Min endstop. They are not the same. An endstop actually locates the print head, a probe compensates/corrects your Z Max Height. I hope this makes sense. Oh, and Max Z height will change throughout the day as your printer thermally expands and contracts. G28 is the homing command that must be done after every power up of the printer and before every print.

Diagonal rod length - The length of your arms from center to center of the balls. This setting effects the "dishing" of you printer. If the setting is wrong your hot end will make a "dish" as it moves in the XY plane. IE, it wont stay level.

Horizontal Rod Offset (Smooth Rod Offset) - The center to center distance from the balls only on the X-Axis. If this setting is wrong then printer wont be dimensionally accurate. A 10mm square will become larger or smaller if it's wrong.

http://chibidibidiwah.wdfiles.com/lo...elta/delta.png This picture does a good job of showing the two distance measurements.

A lot of people are really afraid of delta printer calibration but the truth is it's pretty easy. Get the three settings above correct and then match the plane of your endstops to the plane of the bed, which are never relatively parrallel. The good news is getting the endstop plane to match the bed plane should be pretty easy too. Endstop corrections can be done in the firmware or manually by loosing them and moving them.

Hope this all makes sense! Btw, what kind of printer did you get haha?