Recently I was asked for a recipe to take a 1991-1995 Toyota MR2 from bone stock (160whp) to 350whp on 93 octane pump gas. This is more than double the output of the stock motor. Believe it or not, it's possible. Here are the parts I would recommend:
GT3071R turbocharger kit
ATS ECUMaster ECU
550cc side feed injectors
Walbro fuel pump
170 degree t-stat
ATS modified fuel rail
Open element air filter - Apexi, or K&N. Do not use Blitz or HKS foam filters. They degrade rapidly, do not filter or flow well
ATS throttle body inlet - 91-92 only, the 93+ already has an ample sized inlet.
3" exhaust - the Ebay ones flow great, but tend to drone on the freeway. Berk is better about drone, but twice the cost
GSC/HKS/BC 264-268 degree cams
ATS adjustable cam gears
ATS Side Mount Intercooler with fan and shroud kit - I would prefer to use the top mount, but I put budget in the subject.
Total parts cost is about $7000. I have done this recipe many times over the years. The worst I have seen from this is 330whp and the best I have seen is 360whp. Now, if I had a little bit more in the budget the first thing I would change the fuel system, I would run a top feed rail and 1200cc top feed injectors. By switching to these items you open youself up to the possibility of E85 and lots more horsepower in the future.