Update:

Upon further reflection, mixed with angst and panic, I decided to
pull-out and wait and do more research and take my TIME. I'm clearly
not ready to make a purchase.

I just called the KB office (it's after midnight now) and left an
urgent message, asking them to pull my paperwork and NOT send it on to
corporate or deposit/cash my check. I signed the paperwork at 6:30pm
this evening (well, last evening since it's now after midnight). The
transfer of funds to my checking account wouldn't be occurring until
Friday anyway, which I had advised them at the time I wrote the check.
To make doubly sure, I also just cancelled the electronic transfer of
funds just in case they try to cash the check.

I realize I am now in 'default' of a signed contract; hopefully the
elapsed time of approximately 6 hours from contract sign to my
recission will allow me to exit this hasty purchase decision without
financial liability. KB will not be in posession of the $2,500 deposit
since the check will not clear (and I am alerting them to this again
tomorrow when their office is open).

And since no work has commenced on this house, nor has the paperwork
even been transmitted yet to their corporate office, I'm *hoping* the
sales agent will accommodate me in my cancellation. I can't be the
only person who has ever backed-out of a purchase contract mere hours
after signing... right?

Has anyone here done a similar thing on a new home purchase? Is KB
going to go after me for the deposit now? I would think it would be
more effort to extract a deposit than it would be worth at this point,
especially since no 'harm' has occurred and I'm pulling out mere hours
after signing. Opinions?

Lesson learned. Hasty purchase decisions are never a good idea.