I'd like to raise the tyre size within reason but here we are held to the manufacturer size originally fitted! It's a lot of money to invest and then be told at the french mot that it failed due to the tyres not being correct!!+1 for General Grabbers AT 2's. Good grip in both the wet and dry. Seem to be getting very good mileage out of them and they are fairly good in the snow. What swung it for me was on a trip to Morocco three years back , two vehicles had the AT 2' and they stood up to the rough treatment very well. Better than one guy's BFG AT which were shredding.
I went for the 235 x 85 x 16 for the extra ground clearance. Quiet surprising what just those few mm make.