Megasquirt is a stand alone fuel system which replaces your ECU and gives you full control over tunning your car to your needs. It's cheap at about 150 but it requires that you put the whole thing together yourself, so you have to be pretty good at electronics. Or you can get a pre-assembled kit for about 300 but you still need to know how to install it and tune it yourself. This is more for people who know what they are doing when it comes to tunning a car so if you are experienced enough this would be a better mod to do than the JWT ECU. Lastly megasquirt requires use of a laptop computer for programming so thats something you must have, if not thats an added expense of buying one. Honestly on your non turbo you probably won't see a difference between megasquirt and JWT ECU.
Now for the JWT ECU. You won't find one cheap. Most non turbo guys never spend the money anyway to do this mod becuase of how expensive it is. So don't think you will find someone selling one for 100 bucks or anything. At best you'll see one going on ebay for about 500 dollars every now and then. You have to pay to play so don't be cheap. Lastly, on a non turbo it helps but don't expect a big increase in power. I could barely tell the difference when I installed mine. Still I managed to drop .3 secs by installing it. Also you SHOULD already have intake, exhuast, and headers before doing this mod. If you don't already have these three mods hold off on doing the JWT ECU. The JWT ECU is set up to work with people who have already done these mods so if you try and just put JWT ecu on a stock car it probably won't do much of anything. Good luck, check ebay but I doubt you'll get that lucky, and just save 600 bucks to do it right.