LOL
No you won't lose power or torque. What you will gain is the ability to use 2nd gear all the way up to 60mph. Try doing an autoX with and without the 2-3 shift. In most real world situations where you actually care about gearing, you are using 1st, 2nd and maybe 3rd if you're brave. With the 4.1 you have to shift to 3rd no later than 54mph. So instead of constantly bouncing off the rev limiter or taking your eyes off the road to catch the shift point its easier and quicker in most real world driving situations (35-60mph) to use 3rd gear instead constantly shifting between the two gears at every corner. Now imagine your favorite windy mountain road or an autoX. with a 3.73 (or in my case 3.64) you put it in 2nd gear and forget about it. The only time you need to go to third is when you accelerate past 60mph at which point you are probably on a straight enough bit of road that you can afford to take you hand off the wheel.
Put another way
3rd gear with 4.10 has a combined gear ratio of 5.41
2nd gear with 3.73 has a combined gear ratio of 7.53
There is no doubt in my mind that if you were driving on a track lap after lap and you had your shift points committed to memory, the 4.1 would do faster laps. For the rest of us that live in the real world and have to contend with oncoming traffic, the odd bicycle or deer on our favorite mountain road, 3.73 or 3.64 is ideal.
So with a 3.73 you are giving up 9% of your peak torque in any given gear in exchange 3 more mph in 1st and 7 more mph in 2nd. Did I mention the M42/E30 is quicker to 60 with a 3.73 instead of 4.1? Its that damn 2-3 shift. 80mph at 3300rpm is the icing on the cake.
One of my favorite roads.
http://maps.google.com/maps?f=d&hl=en&geocode=&saddr=Fairfax,+CA&daddr=Bolinas,+CA&sll=37.0625,-95.677068&sspn=33.160552,59.765625&ie=UTF8&ll=37.959493,-122.644329&spn=0.064425,0.11673&z=13&om=1
