There is a benefit for having a wider stance...but after I went with the 1.5" spacers some tests and studies came out that indicated those benefits for having only 3"s more has a far less effect on CG then expected. But it does feel better..at least in my mind. 9 or 10" more and you will be where the EX is. Getting back to wheels, as long as the first number is equal or greater then the second number, you won't add extra side or torsional load to the bearing..which by the way one has already done with the spacers. I have another post where I took actual measurements of the stock wheels on a 53" machine and a +3 or a +4 wheel will add several more inches to the overall width. So with the spacers and stock wheels, right now, my outside to outside front tire measurement is about 54.5". I can add about another 2"s to that if I went with a 5+3 on the back and a 4+3 on the front. You could go to a 4+4 all the way around but you would have to keep all the tires the same...and there has been some talk about the extra width in the rear needed because of the load of the engine being...in the rear. Even or balanced traction kinda depends on load on each contact patch square inch. Some say with all the same size tires it would be out of balance and there may be some control issues with having all the same width. So..you will be safe with having 11s on 8" wheels on the back and 9s on 7" wheels on the front.
For me..I am considering taking the spacers off. I expected reduced service on the wheel bearings but I didn't expect what I am getting... greatly reduced service life of suspension bushings.