all kits require some custom work... because the stock H7s use the adapter thing, which makes the clip push on something thats liek an inch deep. so you have to recreate it, using either a hollowed out adaptor, or using rubber pieces or something. other than that, its pretty "plug and play". plug in the wires to your batter/ground/H7 connector, ballast, bulbs, put bulbs in, secure ballast, and youre good to go!
Actually, that isn't exactly correct. Toyota decided (for what reason I have NO IDEA) to design the housing in such a way as to use a little space between the back of the bulb and the spring clip..........this is where the "customization" comes into play with our 7th gens.
Most cars simply have the spring clip butt up right against the back of the light bulb......in those instances, customization really would NOT be necessary.