Easy stuff really... just need to be ready to click a million time on your mouse
Since EU3 tech can be bought by money, that max tech means you need an exploit to create infinite money. Here's how it works:
-Have a small but rich mono-province (or 2 provinces) with a port, like Holland
-wait for tech gov4 (so you can take your first national idea) and accumuilate money while.
-Pause
-select "Grand Navy" or "press gangs" (same effect for what we want, if i recall well) which doubles your naval forcelimit and start building as much carracks as you can, using all the loans you can. Once you have more than your naval forcelimit in queue, the carrack price start sky-rocketing.
-select another national idea, like "church attendance duty"
-now stop creating all those carracks dammit! you don't want them! luckily, they give you back 50% of what you paid for them. And since the carrack price is linked to your naval forcelimit, they are now worth their weight in gold!
-Pay your stability back to +3
-???
-Surprise! Looks like you have more money than when you first started it!
-repeat...each time you can build more carracks so very quickly that little scheme give you TONS of ducats.
-Buy your tech --> tech maxed
Conclusion:
-works even better with two national ideas (so if you can take "press gangs" and "grand navy" together)
-Can be used to create infinite amount of money... deadly in MP especially with Holland, since generally you don't do a thing before 1500 with it.