i have a 2003 Pontiac Gram Am Eco Tech 2.2 4 cyl. 97,000. no oil usage or issues. i use Moblie 1 extended mileage. my driving is 70% highway, 30% city. my commute to work each day is 40min each way. is Royal Purple a better oil than Mobil 1 and is it worth the extra money? thanks.