ok guys, ive got a honda civic ex 2002 5 speed that calls for 5w20. From hearing the discussions on this board btw dino and synthetic, i have to wonder is it really worth it? I mean, in my manual, it states severe changes at 5000 mi/6 months and normal changes at 10000 or 1 year. Being that im changing the oil out in 2 weeks when i have about 5200 mi on it, im going to be either using the 5w20 drive clean or castrol gtx 5w20 and using a bosch oil filter. I calculated it out, and i can change the oil and filter three times and it would still be lower than getting synthetic oil and changing that twice in a year.(its like 39 for 3 dino changes and filter and 44 for synthetic and filter changes). I just want an honest opinion on synthetics and if they are really worth it. 60% of my driving is highway, and im not in stop and go that much, but i do want the best protection possible, best gas mileage, and no engine sludge.