15% or 17& pulley?????

[DHmtnbiker42]

i just bought a 2002 cooper s. i plan on buying an alta performance pack, which is an msd ignition, pulley and belt. but idk if i should buy the 15% or 17% pulley. i am not going to do any other mods to the car. im trying to get the most power without sacrificing reliability. i have heard that the 17% can run too hot. is this true? which pulley is best???
ALTA Performance — — MINI Cooper S Ignition Pulley Package

[bad venge]

the 15% is closest to the JCW package , best for reliability /longevity
the 17% gives more power , but can take it's toll out of supercharger life