Question Do I have to change the input power from 100 Volts AC to 240 Volts AC (or vice versa) manually, or is my unit auto-sensing/auto-switching

Yes, the units you see below have auto-sensing/auto-switching powersupplies. You just need to get the right AC plug for the country you're in.
    TC Electronic: Bass Amps       ComboClassic       ComboStaccato       Combo450       Classic450       Staccato'51       RH450    TC Electronic: Guitar Effects       G-Force       G-Major (discontinued)       G-Major 2       G-Natural       G-Sharp (discontinued)       G-System / Ltd. / iB Modified       Nova Delay / iB Modified       Nova Drive       Nova Dynamics (discontinued)       Nova Modulator       Nova Repeater       Nova Reverb       Nova System/Nova System Limited    TC Electronic: Audio Interfaces       Desktop Konnekt 6       Impact Twin       Studio Konnekt 48       Digital Konnekt x32 (discontinued)       Konnekt 8 (discontinued)       Konnekt 24D (discontinued)       Konnekt Live (discontinued)    TC Electronic: PowerCore Platform       PowerCore 6000       PowerCore X8       PowerCore FireWire       PowerCore Compact (discontinued)    TC Electronic: Studio, Touring & Install       BMC-2       C300       C400XL       D-Two       EQ Station       Finalizer (discontinued)       Finalizer 96K       Finalizer Express       Finalizer Plus (discontinued)       FireworX       Gold Channel (discontinued)       Intonator (discontinued)       M-One (discontinued)       M-One XL       M300 (discontinued)       M350       M2000       M3000       Mastering 6000 / Mastering 6000 MKII       Reverb 4000       Reverb 6000 / Reverb 6000 MKII       System 6000 / System 6000 MKII       Triple-C (discontinued)       XO24    TC Electronic: Broadcast       D22       DB2       DB4 / DB4 MKII       DB8 / DB8 MKII       DBMax       P2