I've got a jaycar unit. I installed in on my old FJ20 blluebird but haven't fitted it yet to my CA18. They are effective but have their limitations. Because they are not a closed loop system like the top of the range stuff they usually end up giving different boost levels in different driving conditions. It's hard to explain but it takes it's input from the injector duty cycle and uses that to reference a duty cycle for the solenoid output from the map you program. Unfortunately it doesn't consider engine rpm and for this reason it becomes unstable because the same engine load (or duty cycle value) can be found at different rpm depending on driving conditions and gear etc. This means that the same solenoid output is used in different conditions giving different boost levels. They are easy to tune for Wide open throttle for the race track where you are using the same rev range for all gears but as soon as you try to use them on the street where you might put your foot down in 5th doing 2500rpm ,for example, they don't work. They store 2 maps which is useful and one can be set to stock which you could use on the street and not have any of the aforementioned problems and just use the higher setting on the track. But as mentioned earlier we all know the low boost setting quickly becomes obsolete!

I had heard that Jaycar were working a feedback unit for the kit which would be well worth looking at as it may fix the problems.

If you are going to splash out on a decent EBC then it might be worth considering the Eboost2. They are a bit cheaper than the jap brands and give good results.