JGS has an awesome log style turbo manifold for the SOHC
ojperformance.com has a TON of KA24E & DE parts available. More SOHC than DOHC.
Oil lines: They supply the oil to and from the turbo. Very vital for any turbo to work for more than a few minutes.
Oil pan: The bottom most part of the engine. It holds the oil needed to lubricate the engine. The stock pan will be just fine with a turbo set-up. You'll just need to have a fitting welded into the drivers side of it to accept the oil return line from the turbo. No big deal. Just about anyone with a welder can do it.
Manifolds: exhaust manifolds (obviously aftermarket) will hold the turbo and carry the exhaust gasses to the turbo. 3 basic styles log, tubular, and equal length.
Log style is an un-equal length manifold more than likely cast iron. They typically only have 1 "runner" (pathway for gasses to flow) where all 4 cylinders are fed into and the flange for the turbo is welded to.
Tubular style is still un-equal in runner length but has 4 runners that feed into a common collector. The turbo's flange is welded to the collector. Each cylinder has it's own pathway to the turbo making this manifold better than a log style if you wanted big HP numbers I'd say over 300HP.
Equal length style is still a tubular manifold but with each cylinder's runner the same as the rest of them, you get 4 distinct pulses at the turbine and greater flow than both log and plain tubular manifolds. These will be the most expensive but will net the best gains in HP.
If you're going to turbo the SOHC with a stock engine, I wouldn't get more than a log style like JGS Tools sells. There are other companies that sell manifolds but their the only ones I can think of right now.
Down pipes: This carries the exhaust gasses from the turbo to the rest of the exhaust. Since the stock manifold doesn't have a turbo mounted on it, the manifold carries the gasses downward already and to the rest of the exhaust. With a turbo, the gasses don't follow the same path. On the back of the turbine there's a flange. The downpipe bolts to this flange and the other end to the rest of the exhaust. Companies that sell turbo manifolds for the KA24E should also have downpipes.
Turbo timers: Turbos are heat pumps basically. The worst thing for a turbo is lack of lubrication. When you push your turbo hard and then abruptly shut the engine off, the oil remaining in the turbo's center section runs the risk of "Coking" and sludging up. This could then lead to lack of lubrication and then destroy the turbo. The timer, when installed, will continue to run the engine at idle even after you turn the car off and remove the key. It will run long enough to cool the turbo down to prevent the mentioned issues. The run time is adjustable IIRC.
MAFS: Mass Air Flow Sensor. It senses how much air is entering the engine so the computer can add the correct amount of fuel. A MAFS uses a heating element to gauge airflow. The computer tries to maintain the heating element's temperature by adjusting the amount of voltage it sends it. The more air that is passing the element, the cooler the element will get, and the more voltage the computer will send it to bring it back up to the target temps.
MAPS: Manifold Absolute Pressure Sensor. It uses the pressures inside the manifold to gauge the engines requested load rather than exactly how much air is coming in. If the throttle is closed, you have a vacuum, and when the throttle is opened you have less vacuum. The MAPS sees the pressure changes and knows the engine load has changed. Engines typically have either a MAFS or a MAPS. Some use both but not many.
Chips: Luckily us SOHCers can utilize chips. The chip is the brain of the computer. The engines tune is loaded onto the chip as a program and then replaces the stock unit inside the ECU. On the SOHC, we can just change the chip on the motherboard and go. For the DOHC guys, they need a daughterboard for the chip. Please do not be fooled by the ebay "chips" sold claiming 50HP gains. They aren't the same thing AT ALL.
Tunes: the "guidelines" of the program. The tune is what the computer tried to maintain with what the engine is doing. The tune says how much fuel is added per pound of air, how much timing to advance/retard for a given load and rpm, and adjustments for sensor readings (just to name a few).
That's basically it. I could go into more detail about these things, but I'm tired and I don't feel like going into it.
If anyone has something they want to add, verify, or change about my explanations feel free to. I am by no means an expert and I'm sure I didn't explain something right or fully.