What's the hardest car part you've installed solo?
I'm sure I'll see alot of engines and tranny installs but I'm still curious none the less. My hardest just happened last night. I installed a rear end all by myself. It wasn't that bad at first until I had to align and jack the thing up at the same time! And the higher it got the more unstable it became. It nearly rolled right over me. =/ But I got it in and that's all I cared about.
Other than that the other worst was removing and installing a nearly 3/4 full gas tank in an apartment parking lot. That... sucked... ass.