I just found some details on the LRP SPX8 ESC, which kind of destroys it in my eyes.
SPX8:
BEC / Electric power supply of the receiver: 6V/5A
Weight: 45g
Size: 33.1x37.6x32.5mm
Motorlimit: None
Voltage Input: 7.2-14.8V (2S-4S LiPo)
Rated Current: 764A/Phase
Type: Forward/Brake/Reverse
Standard SPX Bullet Reverse:
Weight 45.0g
Motorlimit over 3.0T (Brushless) / over 4.0 (Brushed)
* Brushless + Brushed: Forward/Brake/Reverse + Forward/Brake
* Automatic brushless/brushed swichtover
* Internal-Temp-Check System
* Advanced digital with 4 adjustable modes
* Big power capacitor optimised for Touring car application
* Ice Drive Design
* AutoCell System - Automatic NiMH-LiPo adaption
* Voltage Input: 4.8 - 7.4V
* Low-profile heat sink
* Fan on/off via speed control main switch
* 25 years warranty
* 3x Multi Protection System
* German Technology
Hmm, they are both 45g. Can't be that much to improve the voltage capability to 4S, a new BEC design maybe? Some different Caps?
Also, what's with the crap '764A per phase'? 'Cos that's likely!