Mod your car = waste of money.
Hobby is always a waste of money. Unless you are really good at it to a point you get hired/sponsor by big companies, or you will have to pay for your hobby. The total cost of my S14 now is like 10g now. I could have got a WRX now but that 's not the point. If I had a WRX, I will still put exhaust, EBC, suspension, etc, which makes the car's market value less, and you have to spend the extra money to get them in the first place.
Back to the car issue. It is either a fuel problem or plug problem. My SR had wrong plug and when it hit full boost (stock boost), it will lose power, I mean a chunk and it comes right back up. I switched spark plugs form #5 to #7 (do not know what the guy did the swap was thinking) and the problem went away.
But with that problem and a stock exhaust, I still put down 178 and 178 on dyno with minor mods.