crabman

Folks safely put wheels on cars with far more torque than the RX puts down. I would be looking at forged wheels to keep the weight in check. Just about anything else is going to be heavier than stock. The el cheapo wheels are tempting but can weigh in at 5 or more lbs per wheel more than the stock pieces. Unsprung weight is detrimental to performance in every way, hurting acceleration, braking, handling, economy, and ride. The penalties are greater on a hybrid than a standard drive. If you want to go to a different size solid research would be in order to determine what you might be running into. Remember that the power distribution scheme was designed around the stock wheel sizes. There is also the usual stuff like speedo accuracy that need to be taken into account. Sticking with the stock wheels size and offset or very close to it (normally OEM specs allow around 3% to account for tire wear and inflation) will be best if you want a hassle free experience.

There are sensors that determine the angle of impact and the airbags are deployed only on collisions where they can protect the occupants. Remember that airbags are very expensive to replace and can represent a large portion of repair costs. This is a good thing because they can total what would otherwise be a repairable car and many people do not come out well on a total loss. This also reduces the overall costs of repairs to the insurers which means lower premiums for everyone.

Just purchased the coastaltech "ultimate" setup. I will follow up with my impressions after the install.

The ball was dropped on the nav/bluetooth Zoeydanielle. A well intergrated system is a thing of beauty and expectations are higher amongst users who have experienced such a system. Unfortunately Lexus is behind the curve on this as more and more people are beyond being wowed by the mere existence of a nav system. Stating these facts does not necessarily signify an overall dissatisfaction with the car. If I want to call out in my car I simply push the button, say "call blah blah" and it works every time. On my wifes car (RX) its more miss than hit. It is also needlessly difficult to upload address books or manually enter phone numbers. Does that mean the car entire is junk? Nope. The nav system needs work though and hopefully Lexus will listen to its buyers and try and improve its functionality and ease of use.

Bottom line is I dont know on the vehicles we are discussing here. My wife has purchased an RX and Im just now starting to research the vehicle. Many cars, typically running higher power outputs can benefit from premium because it keeps them off the low tables. Significant power is lost by pulling timing and you dont want that when the point is to have fun on a backroad romp. One thing to keep in mind is that in normal operation on the O2 sensors and fixed tables nothing is lost because the OEMs keep the timing conservative in those operation parameters. This is because we are not asking much from the engine so there is no reason to run a more aggressive timing. It is only at larger throttle openings that power is lost if you have been kicked to the low octane tables. As already stated there is no economy benefit. All commercially available gas has the same energy density and the 02 sensors will keep the mixture as close to perfect (14.7:1) as is possible in a given engine at the same efficiency with any octane. Engine longevity is only affected by octane ratings if the particular setup goes into detonation, this will significantly reduce engine life.

First post here guys. There is a little misinformation in this thread. Gas is a commodity. Trucks from all manner of brands fill up out of the same tanks at refineries and storage depots all over the states. The product is differentiated (one brand to another) only by the additive package which is added when the trucks fill up and is a very small quantity. The octane rating of gas tells you the speed with which the gas burns and its resistance to detonation. Gas of any octane has the same energy density, 45 megajoules per kilogram. This means that premium has no economy advantage. The benefit to running higher octanes is that it allows a higher compression ratio and/or more timing/advance. Any of these things or combinations of these things will bring an increase in power and efficiency. The downside is that as you increase your compression or add timing it makes it easier for the gas to pre-detonate. This is the knock. Modern computer controlled engines run on the 02 sensors most of the time to control the mixture and a fixed timing at various loads and rpms. During large throttle openings or WOT the car runs a fixed value for the mixture based on rpm and has two timing values it can run on. These timing values are a standard timing value set and a low octane table that it can revert to if it detects knock from the knock sensors. On some cars the lower timing value only serves to protect the engine in the event of a bad tank of gas. These cars will not gain any power during large or full throttle applications by using premium because the values were set to be well within safe tolerances using regular gas. On other cars manufactures have taken advantage of the ability of higher octanes to resist detonation by giving them more compression and or timing where they can safely run on premium without detonation but will not running regular. These cars can gain extra power by running premium but it is only seen at large throttle openings. Typically, cars are set to stay on the low octane table till the car is filled up again. Sometimes it must be filled up more than once. At this point it is back on the standard tables until knock is detected again. Engine longevity is not effected by octane unless the car experiences detonation. Your warranty cannot be voided by running regular unless the car requires it. This must be stated in the manual and warranty information. Very few cars do, for most it is recommended rather than required. To go back to the beginning there is no economy advantage to be had from running premium. It contains no more energy and your car is running on the 02 sensors which operate at the same burn efficiency with either grade.