Re: 2015 Sienna XLE - New owner, help w/ Mods in Los Angeles
You can install a front lip yourself -- I'd never installed one before but it was very straightfoward -- just screwing stuff in, then drilling small pilot holes in clearly marked locations and putting more screws in. I think the side skirts are little more involved (or maybe not?), then the rears should be super easy considering how small they are. These are all things a body shop can do for you too though, just go on Yelp and look up a shop nearby with good reviews and ask them if they'll install aftermarket parts -- chances are good that they won't guarantee the work, but whatever right?
The LED strip light is not plug and play, you'll need to find a way to wire it to your current harness (may involve fashioning a new harness) and may need a DRL controller. It'll be helpful to have a DC power source and multimeter. I made a writeup on this board about how to retrofit the light onto a 2011-2014, but things are probably a bit different on the 2015+. You'll also need to buy the lights themselves. New OEM ones are mega expensive, which leaves lights from salvage vehicles, which will probably have broken tabs and possibly even broken cosmetic internals, which will require you to open up the headlight and glue all that stuff back together. Here are two ebay searches that will help you:
oem sienna headlight (2015,2016,15,16) -2011 -11
oem sienna headlight (right,passenger) (2015,2016,15,16) -2011 -11
The passenger one is harder to find than the driver's side one. I'm assuming this is because when a driver swerves to mitigate a crash, they usually don't swerve so that the impact is hitting the driver's side. You'll still have to weed through these to get rid of the LE and XLE lights by photos too, as you're just looking for Limited or SE lights. All in all, this isn't what I'd classify as an easy mod, although it's very cool.
You should probably own your van a little while before deciding to lower it. After installing the front lip and 350Z exhaust on stock SE suspension, I have to drive like the van is a lowered car already, eg going out of driveways slow at an angle, etc. I had RS-R lowering springs all purchased and ready to go, but after a couple months I decided not to install them. Also, I'm assuming your van is primarily a passenger-carrying vehicle, otherwise you would have gotten a different car. Lowering never makes a ride more comfortable. Coils never make a ride more comfortable. Keep that in mind. There's a guy on the Vankulture group on Facebook who's getting rid of RS-R coils, which have the softest spring rates of any coils for the Sienna, because his "old ass can't take it."