How much do they cost and how much for the installation?.I hear the ad on Road dog sirius/xm radio, or should I keep giving speedco $250 for every 15k miles of oil change.

You do NOT have to get one of these units to extend your drain intervals. I know of one guy that put long life filters on his detroit, and went 100,000 kms(62,000 miles) on synthetic without a problem.

Before I had my kleenoil filter, I went about 50,000 km(30,000 miles) on a oil drain interval without a problem. But comparing that oil sample to the ones now, my oil is cleaner(soot %) and the wear metals are down.

So it does make a difference, but isn't required to extend intervals whatsoever.

Which filter would you recommend for a detroit?$250 per 15kmiles is killing me.
I will also assume these filters you would recommend will have something like a spout to open it up to get an sample.

We entertained the idea of putting them on the trucks. But we have one problem with the idea. At 15,000 to 20,000 miles (we service at 20k), all 3 of our Cummins and our Cat as well begin using oil. I don't think a filter would change that.

None of the OEM's have an recommended oil change interval of 15K miles. Why would you change so soon? The lowest oil change interval I have ever used in 26 years was 20K miles. You can get a Wix XD oil filter for your Detroit for about $50 online and it has glass/synthetic filtration media and smaller bypass filter as part of the same filter.

I took a Cummins N-14 to 1.4 million miles with only an accesory drive seal and a couple of injectors for engine repairs. That on 30K mile oil change intervals, Kendall oil, and Baldwin filters. Doing the same now with my ISX using Schaeffer oil and Wix filters. But then, I also disabled the EGR on my ISX and eliminated most of the emission soot problems. I will concur with other message here, that my engine is starting to use a little oil by 30K miles, so I change out. Samples show TBN/TBA ratio would probably hold up to nearly 40K miles and soot levels not bad. Wear metal numbers better with the Schaeffer than I had with Kendall. Do my own services.

There are a number of good filters out there. I have come to believe that Donaldson and Wix are pretty much the top of the line. Baldwin makes good filters also. None of the filters have a sampling spout. You would get something like that with a bypass unit. You can always get a sample pump with small diameter hose for low cost and just take a sample thru the dipstick tube. Or, you could get (and I recommend one) a Fumoto drain valve that replaces the oil pan drain plug. Just flip a lever and the oil drains. You could just open the lever a little and get a sample and close it. Been using these on everything I own including my ag tractor and my Jeep Liberty.

All of the bypass filter units are good. You will see arguments going on between the owners of different units claiming theirs is the best. But the differences are so small. With a Gulf Coast, you will have to add 2-3 gallons of oil at each bypass filter change. At that rate, you have effectively changed your oil in 4 bypass filter changes. That is why they are able to claim such high miles without changing their oil, even though they are changing it whether they know it or not. The OPS and FS2500 units only have about a quart or a little more of capacity, so when you change out those filters you probably would not have to add makeup oil unless you were close to the add mark befor the change. I did try a bypass unit once, but did not notice any real savings and it took a quite a while to really get a return on investment. Wear numbers were not any better with the bypass unit, though soot levels were lower. Would never fault anyone for putting one on, but not convinced from my experience that they are the greatest thing since sliced bread as they would claim. Now, if you were running a log truck, cement truck, dump truck, etc in some real nasty environments, then I wouldn't hesitate to put on a bypass unit... no matter the brand.