m_i_zombie
+1y
Stock horsepower ran between 85-95hsp pending years. The 22ret (turbo) boosted around 115 stock. The 22r motors have been noted to reach 350 - 400 hsp with forced induction, ie. turbo, super charger. A lot of it depends on how deep your pockets are and how much ingenuity you have. Not many companies cater to the 22r these days aside from LC, Downey and a couple others. They are pricey but they have the market dominated at the moment.
The best thing to do to to raise horsepower is increase air, fuel and fire and decrease weight. Things to start off with is an aftermarket intake (Offenhauser, edebrock), Carb (webber, Holley), or use a side draft setup. Aftermarket header, port polish the head and intake, bump up cam profile. Aftermarket ignition, yadda, yadda I think you get my drift.
Look for places that specialize in the supra or celica, they often have go fast parts that really aren't geared toward trucks.