With good pipe extra sleeving isn't necessary, and if the extra sleeve isn't 100% water tight it can hold water. Which is just as bad as very wet soil. All an extra layer of drain tile is good for is bad backfill conditions. Zero drain tile on the market was ever intended on being watertight, hence the reason we use it. For drainage. The ztile is more than just drain tile and far less likely to crack OR crush like the black tile alone. I have not come across a root compromised ztile but I have seen lots of the other. I wouldn't waste time and money with more tile, PVC, SDR or homemade is where any extra gain will come from. Spray foam kits wouldn't be so expensive if it weren't for the EPA regs and building your own would be just like running potable water mains. Stretching and pulling drain tile??? Might wanna. Test first, if you read the specs, it doesn't have ANY strength till it's buried. Our current drain tile with white PVC jacket says 3000psi crush strength, but that's only when properly bedded and backfiled to the ASTM specs.
Victor you might be a good test consumer for the forum. All we would need is an accurate flow measurement ( flow meter / calefi quick setter, zurn, Johnson control type), pretty close footage measurement, and good temp readings. The zpipe is probably the best of the foil wrap types and it has its place for those that can't budget the high dollar pipe. That goes for any part of the system as well. We would all love to buy the top of the line, I just don't like when I get a customer that was sold on the fact that its as good or better, it's just not a cheap component to have to repair.
Whether snow melts on yours or not all depends on the depth, soil moisture , frost line etc. Not everyone can view the pipe thru an infrared camera.