Although I prefer a brand other than Look, those pedals will be excellent. (I have ridden Looks, but hate that eventual squeaking.) And as you said, they match your bike!

8-ply vs. 6-ply? I have always found the 8s more comfortable. I've also found them to fit better. Maybe it's because there's nowhere that the Lycra is too greatly stretched. They also seem to last a good deal longer than 6s. IMHO, paying the extra $25 for a *high-quality* 8-panel is worth the extra money. I have 8s that are still in great shape after 5+ years. The one pair of 6s I have aren't in great shape. (That I have only one pair of 6s seems telling. I didn't know that until I checked to answer your question.) But, it could also be the brand that makes the difference. I have found buying cheap shorts is a waste of money. (I'll *never* buy another pair of Performance shorts.) In cheaper ones, the elasticity tends to go quickly and the shorts won't hold their form as well.

But none of that matters right now. You have new shorts and pedals. Ride!

(Oh, one more thing. If that's the only pair of shorts you have, be absolutely certain to wash them after each ride. *NEVER* ride in dirty shorts. You want to do your best to avoid saddle sores. If fact, you might ask your dad to use that $25 you saved and apply it to another pair of 6-panels. It's tough getting by with only a single pair.)