Thread Resurrection

Pepboys was running a deal this weekend for motor oil and filters. A case of Pennzoil and 2 Purolator oil filters came out to ~$8 AR. I had my brother pick it up because I was out of town but he picked up the 10W-30. I checked with the Prelude owner's manual and it said 10W-30 can be used "if the temp in your area never goes below 20F". Well, southern california is never going to get that cold, but I was wondering if anyone uses 10W-30 and noticed any difference from the 5W-30.