What are the top mods for the Lexus IS 300?

This blog will answer the following questions: what are the top mods for the Lexus IS 300? What are the technical specifications of the Lexus IS 300? What to know before buying mods for Lexus IS 300?

What are the top mods for the Lexus IS 300?

The top mods for the Lexus IS 300 are given below:

  • Intake system
  • Apexi Throttle Performance Chip
  • Exhaust system
  • LCA bushing and anti-roll bars
  • Transmission booster kit

Let’s take a detailed look at each of the mods

Intake system

The intake system consists of an air-filter box, air filters, intake hose, and intercoolers. There are plenty of aftermarket modifications available for the Lexus IS 300. Although the performance gain after installing intake system mods is limited, they improve the throttle response and noise of the engine.

Installing a free flow air filter is the easiest modification for the intake system, K&N makes reusable high-performance air filters that can last longer than the OEM filter. The intake kits can cost between 400-600 USD and installation is easy, all the required clamps and screws are provided with the kit.

The all-wheel-drive Lexus IS 300 comes with an inline 4-cylinder engine, RR racing makes a full intake system for the V6 engine which includes a carbon fiber air intake hose between the air filter box and the throttle valve.

Another popular option is the Takeda Stage-2 Pro cold air intake system, it comes with a pre-oiled air filter along with the air hose downstream of the air filter box. Both the RR racing and the Takeda intake systems cost between 200 -500 USD. The Takeda intake hose is powder-coated with heat-resistant paint.

It shields the intake air from the heat in the engine compartment, cold air is preferred in the intake system as it is denser than warm air. The onboard electrical ECU can easily adjust for the increase in the air mass by injecting more fuel and thus increasing the power output.

Apexi Throttle Performance Chip

The Apexi throttle performance chip is a very popular mod for the Lexus IS 300. The installation does not require any major disassembly. The original Apexi throttle controller comes with a wiring harness, controller box, and a LED switch. 

There are 7 modes that can dull or increase the throttle response. It is a plug-and-play system and no ECU remap is needed to feel the changes in the throttle response. The wiring harness and the electronic control unit are installed between the ECU and the throttle pedal.

It changes the throttle signal based on the mode selected by the driver. There are 3 ECO modes, 2 Boost modes, and two low or high throttle modes. The LED on the switch indicates which mode is currently selected.

The Apexi throttle controller  (410-A001) costs around 200 USD, the switch can be mounted in one of the empty slots on the dashboard for a more OEM look. It is a great mod that can improve the driving experience.

Exhaust systems

Full exhaust systems are available for the Lexus IS 300. The costs of the exhaust systems depend on the parts as individual pieces like exhaust manifolds, end pipes, and mufflers can be purchased separately.

Some of the popular aftermarket exhaust systems for the Lexus IS 300 are the Apexi WS2 exhaust system, HKS carbon-titanium exhaust system, and Tanabe Medalion touring cat-back exhaust system. 

These exhaust systems alter the engine noise significantly as all of them are free-flow systems. There is no back pressure in the exhaust manifold and the exhaust gasses can easily exit the cylinder, making way for the next power cycle.

The performance boost from the free flow exhaust system is also huge. There can be up to 15 horsepower gain and the aftermarket exhaust systems also help in the weight reduction of the car.

There can be an engine check light if a free-flow exhaust system is installed. The engine control unit uses an upstream and downstream oxygen sensor to monitor the efficiency of the catalytic converter.

Therefore, modifications must be made to the lambda control system of the Lexus IS 300 by installing an ECU piggyback or tuning the ECU. Otherwise, the engine check light will be ON and the fault code related to mixture formation will be stored in the ECU.

LCA Bushing and anti-roll bars

This is a very useful mod for the Lexus 300, the stock lower control arm bushings are soft and cause excessive inner wear on the tire. The LCA bushings in the aftermarket are stiffer compared to the OEM bushings.

Some of the popular LCA bushings are from RR racing and Figs engineering. The cost is 350-380 USD and installation is pretty straightforward. Anti-roll bars or sway bars are used for reducing the body roll and improving the handling.

Ebach, Moog, and Evan Fischer sway bars are the popular choices for anti-roll bars. The front anti-roll bar is easy to replace. Installation of the rear sway bar is complicated as it is installed in the rear subframe of the vehicle.

Transmission booster kit 

It is used to improve the shift quality of the transmission. The Lexus IS 300 has very delayed gear shifts from 1-2 and 2-3 gear. Using the throttle tuning chip can help to reduce the shift timing but the transmission booster kit will definitely make the gear changes faster.

Sonnax makes a high-performance booster kit and it costs less than 100 USD. It comes with a large ratio booster valve and a strong pressure regulator spring. The part number is A750-LB1 and installation is complicated but the booster kit is very effective. It increases the pressure in the hydraulic valve body which reduces the filling time of the shift elements.

Drivers can instantly notice the quick gear changes even without any throttle modifications. It comes with an installation manual but it is recommended to get it installed by a qualified technician.

What to know before buying mods for Lexus IS 300?

The important things to know before modifying the Lexus 300 are given below:

  • Always plan and install the performance mods in stages otherwise the performance gain cannot be measured.
  • Installing mods can void the manufacturer’s warranty.
  • There are restrictions on the free flow exhaust systems in some countries, the vehicle can also fail the emissions test as there is no catalytic converter in the exhaust system.
  • If the intake system is modified, it must be leak-tight as unmetered air can enter the system from loose clams.
  • Always use suspension components from a reputed manufacturer as parts like shock absorbers, bushings, and anti-roll bars are under constant stress. Any damaged suspension component can cause the vehicle to lose control.


This blog explained the popular mods for the Lexus IS 300. It is one of the most popular cars for modifications as there are plenty of parts available in the after-market. The six-cylinder engine is in a slightly detuned state but it is durable to withstand increased boost pressure to increase the power output.