If it were me, I'd shoot for a tow vehicle that was rated for 20% more GVW than you will be pulling.
Three aspects you might want to consider.
- Ability of vehicle to pull the trailer up hills etc. Transmission coolers etc.
- Ability to stop (consider your trailer brakes (Electric over hydraulic being ideal for a heavy trailer with a good brake controller))
- Tongue weight and hitch class. This will also affect your ability to stop.
Some ways to upgrade your vehicle.
- Rear airbags if your vehicle CAN be fitted with them
- Better rated tires. For instance, I run tires that can hold 80 psi which along with airbags can help the confidence of the vehicle a lot.
- Trailer upgrades include 4 wheel disc brakes and a good braking system. If going disc, make sure the system is designed for disc brakes.