I bought two also of the 6 in 1 espalier apple trees. My problem with mine were the bottom tier on both of them were too close the ground and the next tier so I removed the bottom one on both. I just allowed any growth nearest to the middle to grow and in one summer I had growth from both trees to go up another tier and then just bent the limbs growing out of the new limb at the right height. In the second year I all ready have growth for another tier.

Consult your owner's manual. It'll state a recommendation for the engine or engines when the car may be equipped with alternate engines. The grade of fuel needed is related to compression ratio and super/turbo charging. High compression engines need treated fuels to prevent self detonation. A lower compression engine with super charging also needs help for the same reason. At sea level, self ignition begins at compression of 14 to 1, the fuel will self ignite without a spark because at that compression, the compressed air rises above the ignition temperature and the entire charge goes BANG instead of a smooth spreading flame front. As you go up in altitude, the air thins out, there less of it to cram into the cylinder and the self detonation potential decreases. Typical pinging happens when during the first instant of ignition the cylinder pressure rises and the remainder of the charge explodes all at once instead of a smooth spreading flame front. An engine at sea level needs more anti-knock help than one at 10,000 ft altitude. However, a really active supercharger changes the picture. The compression ratio may increase if deposits accumulate within the head. Also, deposits can get hot and continue to glow enough to cause ignition. Catalytic converters oxidizes unburned fuel and tries to complete the combustion of CO (carbon monoxide) to CO2 (Carbon dioxide). Converters fail by overheating or reduced operation. Overheating is caused by too much unburned fuel dumped in to the converter or sitting still for long periods of time with the engine above idle. The usual death of a converter is from contamination of the catalyst rendering it ineffective. Also, the converter can become clogged with deposits. Its passages are small compared to other components of the exhaust system. Never pour any additive into the gas tank unless it specifically states it is safe for the catalytic converter. Some are not. A number of converters were killed back when filling stations were switching from leaded gasoline to unleaded. (From before WW2, a lead compound had been used for anti-knock, but lead is one of the things that will coat a catalytic surface and render it useless. Once this happens in an automotive converter, its begins to plug up.) During the change over in fuels, due diligence was not always applied or understood and the fresh fuel was contaminated with the older fuel that remained in the partially emptied tanks. Mix-ups continued either accidentally or by intent until leaded fuel was completely phased out.

I mentioned something earlier that didn't seem to be noticed so I'd like to mention it with more details. There is a specification for gasoline that's called Top Tier. What it is is simple - it's a formula of detergents and additives that are put into gasoline (with no pollution consequences pro or con) that prevent carbon and other deposits to allow the engine to run at its peak efficiency. Gasoline without these additives causes the build up of various deposits that can lead to premature problems and lower fuel economy. Many of the discount gas brands are NOT Top Tier gas - especially from grocery chains - and using such brands consistently can lead to problems and lower gas mileage along the way. Some, like Costco, do use the Top Tier additive package. If you're concerned about saving money, be sure to drive a car that isn't bigger than your needs require, that gets good mileage and that you keep well maintained. And use Top Tier gas. These steps will save you far more money than worrying about whether you've gotten the lowest possible price for gas, which may result in your buying an inferior product that could cost you more in the long run. We own three cars and all are makes that suggest using only Top Tier gas, so that's all we buy. Top Tier-selling stations are all over so it doesn't take an effort to restrict purchases to just this type of gas. Here's a listing of gas retailers that sell Top Tier gas Top Tier Gas retailers Here's an article describing it: Top Tier gas

eld, a few reactions to your comment. First, if you don't drive much in traffic or with stop and go conditions, it won't do much for you. Many people do drive in situations like that, especially those who commute to work in urban locations. Cars burn gas when idling so whatever is saved is more than nothing. It's low hanging fruit, the feature is cheap and will help and can't hurt. Second, it was developed in Europe, where auto engineers have been focused for years on wringing more performance and more efficiency out of engines. I have a few year old, not small German car with an engine that's maybe half the size of what was put in the same model a dozen years ago. It gets amazing mileage, in the high 20s in town and mid to high 30s on flat highways (at highway speeds). With a turbocharger, it's very fast and responsive at lower speeds. When I lived in Europe a few decades ago, I remember that when stopped for other than a short interval - a draw bridge, a level train crossing, a long signal- drivers turned off their engines. The start stop feature does that automatically for those who, like you and me, appreciate not having to think about it. It's not a big deal but I think it's a thoughtful one.