Yeah definitely,
G15 + G8 = 240 + 140 = 380
G9 + G8 = 160 + 140 + 20 (5" backing plate) = 320
$60 its not a big deal...
So if I understood right you say the G15 has noticeable more power than the G9?
Obviously Im not saying the G9 is weak or anything just that the G15 is noticeable more...