The 4 cylinder 5E and the 5M wheelbases are longer than the 3 cylinder 5Es, overall length on a 3 cylinder 5E is 143.3", a 5M is 149.5", and a 4 cylinder 5E is 159.1". The brochure for the 5M doesn't list width but the 5E brochure lists the exact same axle flange distance on the 3 and 4 cylinder 5Es so the width will only be different if different-sized tires are installed (at most, you'd end up with just under 3" wider on a regular 4 cylinder 5E with 18.4-30s vs. 16.9" wide tires on a 3 cylinder 5E.) The height on the regular open station 3 cylinder 5Es, 4 cylinder 5Es, and 5Ms are very similar as well with the ROPS up, they are 99" plus or minus three inches, although the 4 cylinder units are about 6" taller with the ROPS folded than the 3 cylinder units are (no information in the 5M brochure on this.)
Deere does make several narrow and low-profile 5 series tractors in the 75-130 engine HP range. The 5075EN is the low profile narrow version of the 5075E, it is only 61" to the top of the folded ROPS and can be narrowed up to only 51" wide. There are also the 5G narrow and low-profile tractors from 50-100 HP and the 5ML that are either low-profile or narrow low-profile and the top of the folded ROPS is only 40".
An open station 5055E makes a lot more than 30 PTO HP. Nebraska tested an open station final Tier 4 unit like yours and it made 51 PTO HP. An open station 5075E made 64 in their testing.
Deere separated out the 5045E, 5055E, 5065E, and 5075E into different parts books for the Final Tier 4 models (they were in the same book for the Tier 2 units) but the major engine parts such as the turbocharger share the same part numbers so it appears the engines are identical except for ECU tuning. This is not surprising since the 3029 engine is pretty lightly tuned even in the 5075E, it only makes a little over 25 HP/L. Deere offers stock tractor engines making over 40 HP/L.