This is actually quite a confusing topic, hence the mixed answers.
The LRP Shark and the Anderson MB4
are the same as is the Duratrax Vendetta.
Here in the UK neither the MB4 or the stock Shark are available. The only Shark available from UK distributor is the Shark ST.
The LRP Shark ST is the same as the Anderson MB4 ST and the Duratrax Vendetta ST, these three cars are the most competetive for racing here in the UK as they have a wider track.
There is also available the LRP Factory Team version of the Shark and the Shark ST, these cars have many of the comon upgrades fitted:
Ball diffs
Steel U/J driveshafts
Aluminium Shock bodies
Aluminium Steering parts
Anti roll bars
Carbon fibre battery strap
Carbon fibre shock towers
Carbon fibre front top plate
+ more
Hope that helps Stikkan