Vehicles specifications do not change from T20, only their character.  For instance, the T20 Battle Dress becomes Terminator Armour in w40k d20.  Many w40k vehicles have a distinct World War 2 look to them, unlike the clean Star Trek styling of the standard T20.  Nevertheless, despite what they look like they are just as every bit as advanced.  I have included a list of some T20 vehicles and their equivalent w40k name and look as examples.

Terminator Armour As Battle Dress on pg. 285 of T20.

Venerable Dreadnaught Not in T20, essentially a very large and powerful Battle Dress.

Landraider As Tracked Armored Fighting Vehicle, pg 293 of T20.