I found the Rotella T 10w-30 at a great price. $22 for 12q or $45 for 6 gallons. $1.90 and they say this is synthetic??? I was told batch is definately SL too, whew. I liked the Rotella T 15w-40 that I have used, but the dino 40 weight I have been using for ARX is killing my mpg and robbing my mid-range power. At high revs it is very smooth though. I am trying to stay away from ester oils for at least 1 oci after ARX, but cooler weather will be coming... heck, at this price, I might use it for my rinsing phase too! For ARX, I went with Havoline 5w-30 + 1 10w-40 and I can hear every bearing and tick inside my engine. Hopfully the ARX will quiet it down. I am excited about the 10w-30 Rotella T. Is it really the synthetic "T" for this price?