Congrats on college and choosing an awesome platform
Break-In period:
Follow at least 1k miles of not going past 5-6k rpms if you can help it, and vary the RPMs quite a bit. Don't worry about techniques to seat the seals- they do that at the factory and loading dock now
. The clutch will especially be sensitive to break-in and can run a risk of glazing if not taken lightly for the first 500 miles or so. The transmission and rest of the drive-train will smooth out over a longer period of time- around 10-20k miles.
Warranty:
We need more info. Do you plan to modify the drivetrain significantly (FI, N/A tune, extreme suspension setups)? If so, then don't worry about the warranty. Market research shows those plans pay out at a disparately low rate across most people.
If you aren't going to modify the car's drivetrain heavily, then go for it. Not a bad price for an extended.
And best place to buy stuff is all over the internet. FT86Speedfactory, DSG, Corner3Garage, Ebay, fteightysix, diodedynamics, HID Powerhouse, all have different deals and whatnot, but most will float around the same price. japanparts.com for the import stuff.
Have fun man, again, welcome