As for snatch straps, the national standard is 2.5 times the gvm of yoyr car. As such, the gvm on the navaras is approx 3 tonnes, therefore you want the 8000 pound strap. Yoy want the strap to be the weakest link, not the recovery points.
Also, if the strap is too strong, it wont stretch like it is meant to and will shock load your recovery points which will increase the chance of damage.
If you are new to 4wding, do yourself a favor and join a 4wd club. Most will do a driver awareness program which will teach you all the basics and how to recover a car safely.