As usual I have a comment contrary to general opinion, which is that the throttle isn't limited in any gear. Uprev logs show that you get wide open throttle in all gears, well actually I can only speak for my car, but theres nothing special about mine - its a prefacelift DE. The difference in the low gears is that as standard the acelerator pedal movement is not linear with throttle opening, in first you can press the accelerator 3/4 way and only get slight throttle, making the car feel very lazy. But if you put your foot right to the floor you DO get full throttle. The Uprev throttle maps makes the car more responsive in low gears, but does NOT actually give any more throttle opening.
What ROM was that on? Was that before UpRev was applied? AFAIK, UpRev by default (ie their default maps) removes the throttle restriction. Abbey or RSTuning will be able to confirm what really goes on, or even UpRev themselves, as they are on the forum, but not often.