Hi Guys new here but have had my 2008 Nissan Altima Hybrid with technology package since last year

. Living in maryland and had to travel to New Jersey to get it and it is worth every cent

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I am thinking about putting some Wheels on it but not sure what is the proper course of action to do so. What will happen if I put 18' Wheels on my NAH? What procedure should I follow I want to have fun with my Hybrid, get a few outside items not too much but I want to show the world

I love my hybrid and I want it to even look even more unique than my other cars. It averages about 37.5 as long as I drive with some sense, about 34.3 if I drive my age. Would I lose my warranty? Can it hurt the car?
Another serious concern is my EV mode does not come on as much lately. When I normally start up the car wait about 2 minutes and then it kicks in and then I start to drive. Normally, I can get a fair distance before ev mode cuts off as long as I do press gas pedal too hard. Which I try not to do when I can stay in ev mode and save a lot of gas but lately, it just will not click to ev mode like it has in the previous year. I hit my 15k mark. I'm actually over about 100+ miles and I'm taking it in this wednesday I will get it through its premium maintanence. The oil is over about 100 miles so I'm at 3850 compared to the 3750 I normally take it to get it worked on.
Fellow Hybrid owners hit that start button and help me out oh yeah dont forget to hit the brake before hitting that start button

. I know it is cheesy but in a generally good mood it is Friday after all.