if you don't hit now with the 727, you won't, or shouldn't have any issues with the 518 unless you want to add a shield. but if you really would like extra clearance, i guess i would go with the a-500 crowd. too bad you aren't closer, as i have a dealer takeout a-500 i picked up over 20 years ago. it is complete and i'm not sure if i'll go through it or not, as my projects are too stacked up.