According to Ford, the mustang is longer to yield more interior room. Now assuming that the dimensions in the new MM&FF are the production numbers the 05 will not have that much more interior space, at all. The only big difference will be in the trunk volume, that's it.
Wheelbase 05=107.1 in 04=101.3in
Overall length 05=187.6 04=183.2
Overall height 05=54.5 04=53.1
Overall width 05=72.1 04=73.1
Front head room 05=38.6 04=38.1
Front leg room 05=42.7 04=42.6
Front shoulder room 05=55.4 04=53.6
Rear head room 05=35 04=35.5
Rear leg room 05=31 04=29.9
Read shoulder room 05=53.3 04=52.1
Trunk volume (c. ft.) 05=12.3 04=10.9
Umm, so where is the extra room again? The 05 is too long in my opinion. They need to make it small again, it looks smaller than the 04 in the pictures, but it's half a foot longer.
I love the car overall, it's just becoming too big.