0W-30 will perform better then 5W-30 at higher temps. A very good all year round oil. 0W-40's viscosity is even better then 5W-30 at high and low temps. I will see if I can dig up a graph my dad made for me comparing the different oil weights(I posted this on modularfords when someone asked a similar question). As far as clearance being tight I doubt you will have problems with oil not getting in even if you run something heavier.
