[This is a guest post from D Salmons over at TestFreaks. If you are looking for other car gadgets reviews, such as GPS devices, give them a try]

If there are two things that we guys really like, it's cars and gadgets. And when you combine the two and give us gadgets for our cars, well, that's Heaven on four wheels.

With that in mind, we thought we'd take a look at some of our favorite car gadgets.

PLX Kiwi Car Computer

If you've bought gas in the past three years, then you know how expensive the stuff is getting. But have you given much thought to how much you can save by only altering your own driving habits? Well, the savings can add up quickly, and all you need is a good coach to show you how to do it. Enter the PLX Kiwi.

The Kiwi plugs into your vehicle's power socket, and gives you a colorful instant scorecard on how you're driving. The device will take into account your acceleration, braking, and overall vehicle operation, to give you a score. With a little practice and interaction with the PLX you will soon be a smooth (car) operator.

Car Microwave

What's better than to be able to cook on the road? The WaveBox Microwave Oven will plug into a 12v car outlet and fire up your burritos without you even slowing down. The 660 watt oven has a 6x10 inch internal cooking area, allowing you to fix a variety of fine foods while traveling.

And of course, cooking on the go is great, but only if you have someone else in the car with you. It should go without saying, you really shouldn't cook and drive. So save it for your next tailgating stop, and you will be dining before your buddies even get the charcoals lit.

Car Fridge

If you've got the microwave, you're gonna need something to keep your burritos cold until it's time to eat. The Mini Fridge from Think Geek is perfect, with its 20 liter capacity and digital temperature display. The unit has an adjustable shelf, and most importantly there really is a light that comes on when you open the door.

Fuel Checker

You pull up to the pump, jump out, and in a rush grab the nozzle and start pumping your gas. After a few minutes have passed you realize that you have been pumping diesel instead of gasoline. Now you will have to drain your tank and refill it before you can go anywhere.

Unlikely scenario? Maybe. But according to the statistics, around 150,000 people do this a year. But you can introduce a measure of security in what goes into your tank with the handy Petrol Checker (or Diesel checker, as required). You simply install it in your fueling area, and then hold the nozzle close to the checker when fueling up. If it turns green, fill away. If it turns red, then step back and examine what exactly is going on before you do something bad.

Anti-Glare LED Light Panels

The reason the glare from oncoming headlights is so bad at night is because your eyes have become adjusted to the darkness. (Think snow blindness in reverse.) But a German engineered solution called the Anti-Glare LED Panel claims to help with that problem by providing a higher level of ambient light, making sudden headlights less of a shock to your vision.

Of course, it may stand to reason that your eyes would be slightly less sensitive to things on the road when there are no headlights coming at you. So I guess this is a better choice for city driving where the frequency of oncoming traffic outweighs the long stretches of empty road.

Car Projection Clock

Tired of squinting at the dashboard to check the time while driving? Me either. But the Brando Car Projector Clock lets you shine the time anywhere you want. Ceiling time? Sure. Passenger seat? Absolutely.

The unit comes with everything you need to mount the base (okay, it's basically double sided tape), and a five foot cord that plugs into an available 12v socket. Where you shine it is up to you, but we suggest you avoid trying to make your own heads up clock display. No matter how cool it seems at the time.

Xtend-A-Trunk

Most of the time the stuff you need to haul in your car's trunk will fit within the designed space. But, there's always that time when your buddy is getting rid of that elephant foot table you've had your eye on, and there's no time or money to rent a truck. This is where the Xtend-A-Trunk shines.(Literally... it has a light.)

The Xtend-A-Trunk by Totes is basically like a tape measure, but instead of tape you have a strong steel cable. Connect the cable to the trunk and the trunk lid, and it will keep your lid down and whatever you're hauling in place. The unit also features a red light to let motorists behind you know that, yes, there is indeed something big sticking out of your trunk.

Tiwi Driving Monitor

Got a buddy who is constantly asking to borrow your car? A slightly irresponsible buddy? Keep an eye on your four-wheeled investment with a Tiwi Driving Monitor. The device uses a GPS and calculates the vehicle speed. If the speed is excessive, Tiwi will first give a verbal warning. If the driving habits don't improve, then Tiwi will call you up and rat out the driver. It is the perfect eyes and ears, when you can't be in the car.

AlcoHawk

Normally you have enough sense to know when you've been drinking and shouldn't be driving. But if you really have to have a second opinion, don't even bother asking your buddy - he probably had more than you did. Instead, whip out the AlcoHawk and do a quick breath analysis.

The digital display will read .00 to .40 percent Blood Alcohol Concentration, giving you some idea of what kind of shape you may be in. [Here's a tip: If you're thinking you need this thing at all, don't drive.]

RoadScan

Everyone has heard about the black box that airplanes use to record the last few minutes of flight. But did you know that there was a car version? RoadScan is a device that will give you video right before, and right after, an accident... as well as vehicle data including deceleration, date, and time.

The only thing I see that is missing is a quick erase button, just in case you don't want those last few moments saved for review later.