I originally had a 2.0 four. then a stock 2.0 six, then a worn out 2.4T now a 2.4 mod S.
On a yippee scale of 1 to 10 with the stock 4 being 1, the stock six is a 2 1/2. The sound and six feel being the biggest part of the difference ( some improved performance but not much). the 2.4T was a 4 on the scale = improved torque and driveability. you could feel the potential but still sorta blah.
The mod S is a solid 9 on the scale. It makes amazing torque in 2nd and 3rd, pulls 4th hard to redline, the sound is way cool. Huge difference from the stock six. Street driving below 6500 RPM, the stock cooler works fine. 9.5 compression and 93 octane pump gas.
I suspect that a 2.2 would be very close to the 2.4, just less torque.
I highly reccomend the DC30 Mod S cams - very fat in the torque range with near the HP of the S with no real need to rev to 7500 rpm.
I could not imagine going to all the trouble building a GT clone and then putting in a stock 2.0 or 2.2.
Depending on what you start with, The $$ difference between a stock 2.0 and a 2.2 Mod S is not much - port the heads, buy the cams then go have big fun.
I am swagging a bit on these numbers but here goes
1.7 four - 80 hp. 75 ft lbs tq
2.0 six - 103 hp, 90 ft lbs
2.2 T six - 125 hp. 115 ft lbs at 6500 rpm
2.2 S - 170 hp, 150 ft lbs at 7000 rpm
2,4 mod S - 180 hp, 165 ft lbs at 6500 rpm
Hp and Tq are pretty much linear, fun is exponential