I bought my 2007 Jeep Compass with factory tires size 215-60-R17. Its time for me to buy new tires and a local tire shop quoted me 4 tires for $350 out the door. Only difference is the size is 235-55-17. The mechanic told me that they are wider tires so it will handle better and get better gas milage. Can someone tell me the difference between the two sizes in regards to how they look and handle? Will I be making my car worse by putting on different tire size or should I just stick to the original 215-60-17 ?