04-18-2007, 01:05 PM
You won't gain 12hp from changing oil unless you were using tar as a lubricant. Hp gains are all relative also. Maeng's miata might see a 1hp difference in a mod, where Lee's STI might show 6 or more for the exact same mod. I would think a 7 hp difference on a Miata would be a considerable, and noticable, chunk.