Because this card inflicts Piercing damage, use "Micro Ray" to get what is essentially a direct attack.
You can get the necessary Fusion Materials easily by Summoning "Expressroid", as its effect can return "roid" monsters back to the hand.
You can Summon this card easier with "Future Fusion" and filter your deck of the weaker "roid" monsters. If you Summon Expressroid on that same turn you can retrieve two of the "roids" discarded.
Use "Chain Material" and "Vehicroid Connection Zone" to Summon this card and you will easily have a semi-invincible monster. You'd have to wait a turn before you could attack, but since it can only be destroyed by battle and its original ATK is 3600, you shouldn't have to worry.
When using the above technique, while it may seem that this card is always more viable than "Super Vehicroid Jumbo Drill" because of its ability to steal opponent's monsters, keep in mind that even with all that field control this card won't do very much damage quickly; if you want to end the Duel quickly, opt for "Jumbo Drill", while if you prefer field control, go with "Stealth Union".
As this card's ATK is only halved when it attacks, not when it is attacked, you can form an OTK with "Ojama Trio" and "All-Out Attacks". Have "All-Out Attacks" and "Super Vehicroid-Stealth Union" at the ready, and activate "Ojama Trio" on your opponent's turn, for a total of 11,700 damage.
Note that, unlike most equipping cards, this card is not restricted to one monster attached to at a time. Use this for increased field control.