The ease of installing modified LED headlights on a Toyota RX350 can vary depending on your level of automotive knowledge and the specific headlight kit you choose. Here are some factors to consider:

1. Plug-and-Play Kits: Some aftermarket LED headlight kits are designed to be “plug-and-play,” which means they are intended to be relatively straightforward to install. These kits come with connectors that are compatible with your vehicle’s existing wiring, and no major modifications or additional wiring should be necessary.
2. Vehicle Compatibility: It’s essential to ensure that the LED headlight kit you choose is compatible with your specific Toyota RX350 model year. Different model years may have variations in headlight designs and wiring, so a kit designed for your specific vehicle will make installation easier.
3. Professional Installation: While some people opt for DIY installation, it’s often recommended to have LED headlights professionally installed. A professional technician will ensure that the headlights are aligned correctly and aimed properly to prevent glare to oncoming drivers. They can also handle any necessary adjustments to the headlight housing.
4. Wiring and Adapters: Depending on the kit and your vehicle’s configuration, you may need to make minor adjustments or use adapters to connect the LED headlights. This can add complexity to the installation process if you’re not experienced with automotive electrical work.
5. Access to Headlight Assemblies: Accessing the headlight assemblies on some vehicles can be challenging due to tight spaces or other vehicle components in the way. This can affect the ease of installation.
6. Alignment: Properly aiming the LED headlights is crucial for safety and to avoid blinding other drivers. This often requires precise adjustment, and professional tools may be needed for accurate alignment.

If you’re comfortable with automotive DIY work, have the necessary tools, and the kit is designed to be plug-and-play for your vehicle, you might be able to install modified LED headlights yourself. However, if you have any doubts or lack experience in working with automotive electrical systems, it’s advisable to have a professional handle the installation to ensure it’s done correctly and safely.

Ultimately, the ease of installation will depend on the specific kit, your vehicle, and your level of expertise. Be sure to carefully read the instructions provided with the LED headlight kit and consider seeking professional assistance if you’re uncertain about any aspect of the installation.