if you do the spring over lift what would be the tallest tires you can use without problems of rubbing or a little rubbing . and with this said i plain on only going through deep mud , water holes and just driving through the mountain trails and roads made by other 4 wheelers . im not into rock crawling and seeing how hard and far i can push my truck until it gets stuck or something brakes . just love to go trail driving with other friends and just dont want to get stuck or stranded deep in the woods and mountains . also we climb pipe lines and old logging roads the mountains of west virginia , kentucky , ohio , virginia and Tennessee . i also dont need 36 inches of articulation in the suspention to go through places a billy goat would have a hard time getting through . dont get me wrong im not afraid of doing some good hard off roading but just i use my comon sense and know when to say when . im going to have a 10,000 lbs winch for when i do get stuck and to get unstuck with out breaking something . so do you think xzl's 1600 x 20 would be to big , what would the biggest you would go . but what would you have to do to be able to run xzl's 1600 x 20 on a m715