It is modify not modificate, by the way.
If you aren't willing to have an engine swap done legally, you really have two options. You could do a mild N/A setup but you won't get the kind of power you are looking for while keeping it streetable, reliable, and affordable. You could consider doing a simple, low boost turbo setup, rerouting the blow off valve so it will be stealthy, and removing it and replacing the stock parts every time emissions testing comes. That will get you your goal in power at an affordable price, but you would have to make sure you don't draw attention to the fact it is turboed.
Since everything is so strict over there, you should either get used to the fact that the Integra isn't going to be as quick as you want it to be and leave it stock or, sell it and buy a faster car.