Abdul,
While it's hard to compare 1st vs. 2nd Gen, the difference in either (the tune) is pretty darn big.
Several months back, I ran my car on the dyno at one of Mach V's dyno days events. I had an aftermarket intercooler and DoS CAI installed for the baseline pulls. Then, we shut it down and I installed an "out of the box" tune from Alta - using the Access Port and it was an instant 10% gain in HP and 20% gain in Torque that was verfied in subsequent pulls on the dyno. No guessing, no estimating, just hard numbers. Considering the cost of that generic tune and what it did, oh yeah baby, it's worth it! A custom tune on a dyno is even more impressive because you do have so many performance mods.
When you get this done, please post your dyno sheet or at least the baseline and tuned numbers so we can all stare in amazement!
Craig