GT4 useable cheat

-Hint: Tune car while at house: While at your house, hold L1 + L2 + R1 + R2 + Select + Start to be taken to the car setup/tune page. This saves a lot of time, as you can set your car up for arcade races without first starting a race, then tuning, then going back to the main menu.

-Hint: Wheelie at 360 mph: Go to Toyota's classic cars and purchase the Toyota GT-ONE Race Car (TS020) for 4,500,000 credits. Buy everything available for the car including the R5 racing tires. Once you have purchased and souped it up, go to the Power and Speed Icon in the top right corner of the map. Select "Driving Park". Then, select MAX Top Speed Challenge to the right, but go backwards on the track. After the loading screen, go to settings (little tool box). Equip and set the following: Tires R5, Nitrous (set the value to 50), Turbine Kit (Stage 4), Suspension (Racing); set the spring rate and the ride height to the lowest possible value (4.0) and (55) respectively; full Customizable Transmission (set the final gear to a value of 3.000) and the (Auto to 25), Driving Aids, (set all three to 0), Down Force (set front to 38 and rear to 88); and leave everything else stock. When you enter the track, accelerate as usual, but go backwards. Wait until you are on the back stretch to use the nitrous to get it over 360 mph and into a wheelie. As you round the last corner leading into the beginning of the back stretch, hit the nitrous and watch the nose of the car and the speedometer rise.

-Hint: Drifting: With a 4x4, you must enter a corner at a fast speed and exit either faster or slower. With FR, MR, or RR you must enter the corner at a moderate speed but exit faster than you entered. Also, for better performance set your Drift or 4x4 for front wheels to 50.

-Hint: Better handling: When racing on tracks with a lot of turns and twists, use the nitrous while turning. Your car should handle a lot better.

-Hint: Missions Hall: Skyline GT-R Test course: There are five opposing Skyline GTRs on the track. Straight at the start of the race, make sure you stay directly behind the GTR in front of you. It will block the wind and make you go faster, making it easier to catch up. When you enter the first turn, they will slow down. Go to the outside of the turn and pass them from the outside. You will then see the red GTR in the front. Keep going as fast as you can and hit it at full speed. You will get a five second penalty, but it will not bother you much. Hitting the red GTR will send it ahead of the pack. When the penalty is gone, get behind it and catch up to it, but do not pass it. Instead, get behind it and "push" it. Stay directly behind it all along the three laps. In the straights you should be able to reach 275km/h. Upon entering the very last turn of the race, go to the inside before the red GTR brakes, and stay to the inside of the turn. Do not go where it is flat; stay in the bent. Near the end of the last turn, you should be close enough. Get behind the yellow GTR and you should be able to catch up to it before crossing the finish line. This test is very difficult and may require a few attempts.
-Hint: Speed up B-Spec races: While in a B-Spec mode race, press R1 to switch to "Race Monitor". Hold L1 + D-pad Right and you can make the race go up to three times faster. The only downside is that you must stay on the Race Monitor screen in order to keep the race speed up. It will switch back to 1x speed when you go to "Broadcast View" mode.

-Hint: Recommended modifications: The first mod that should done to any vehicle is a spoiler kit in the GT Auto department. They cost 1,200 credits and give the greatest value for the money. Choose the ones to the far right, as they have the greatest downforce characteristics. Most cars can get a kit installed. Save money and do not purchase a Stage 3 NA kit and a supercharger, as they cannot be installed at the same time. Also, when going for the turbo upgrades, look for a fifth kit called " Original". This is usually cheaper than Stage 4. If you have the money to get this straight away, it is better to do this first, as it does the job of Stages 1 to 3 combined, and then some. A recommended strategy for a broad spectrum of cars is (in order): spoiler, full custom gearbox, computer chip, full custom suspension, NOS, race exhaust, then start on the engines.

-Hint: Special rims: The "Today's Special Rims" rotate every thirty game days. There are thirty different sets of rims. There are 439 total "Today's Special Rims". If you see a set you like, you will only see them every twenty nine game days -- buy them while you can.

-Hint: Extra horsepower: Give your brand new car an oil change immediately when you get it (before driving it). It will usually gain between 5 to 30 hp. Remain in current gear with automatic transmissions: When racing with an automatic transmission, hold R2 to force the car to remain in the current gear. Release R2 when the small red light to change gears flashes or the car will not change gears. This useful for remaining at a given speed through a corner, or stretching the top end of a gear for a little extra speed or performance.
-Night/infrared vision replays: During replays, quickly press Square(4) to see a night or infrared vision replay.