I had to do the timing chain (under warranty) on my '08 (late '07 date of manufacture) ... but with that many miles on the one you're looking at, if you can't hear it already, it shouldn't be a problem for that particular motor. Even if it is, use it as a negotiating point, and (if you want) get them to fix it as a condition of the sale ... or knock some off the top and get it done once the bank account recovers. I have yet to hear of someone putting off the timing chain repair and having catastrophic motor failure as a result (some for 10s of thousands of miles). However, caveat emptor, the VQ is an interference motor ... if it does let go, the pistons could hit the valves. But it's not like belt driven motors, where the belt is guaranteed to fail if you let it go long enough past the change interval ... by design, the chain driven motors (at lest to my understanding) should have their chains last the lifetime of the mill, if no major motor mods are introduced. If you do need to have the timing chain done, I've heard it in the range of ~$1k to $14 or $15-hundred to have done in a shop. Much less if you source the parts and attempt it yourself.
The stick is the right call ... as someone said you'll get a better axle ratio than any of the AT trucks (the m226 is the Nissan variant of the D44HD, came in all manuals and with a factory e-locker in all Offroad/Pro-4X models; the c200k is the other axle, and it came in all non-OR/P4X AT trucks). Plus, I've anecdotally noticed that all MPG reports for MT trucks seem to run about 1-2 MPGs higher, on average, than those from the AT guys. Besides, what enthusiast doesn't like to row their own?
