I have had 2 old MGTs, and it handled the Lehner 2250 without any problems on 8S-12S... so it should have no problem running the tekin truggy motor... and stick to 8S 5000mah, save on some weight and use a Neu 1527 for some added power, Just a suggestion... :)
A 1717 would really turn it into a true Monster GT! Plus they are still on sale. I have seen a few people post about running the 1717 on 8S with good results. Just note that it's pushing it to or above max rated specs (6S, 45k RPM).
The 2028 is just way too large and heavy IMO. Even if you made a custom mount and got it to fit it would mainly serve to make the truck heavier and higher COG, and stress the drivetrain. You can only put so much power to the ground, after that it's just going to be shredding tires and gears. The only reason I could see trying that is for the novelty of saying you did it, but if you plan to actually have a fun, drive-able basher stick with the 15 or 17 series.
The 1717 on 6s with a MMM would be my choice. Cheap and plenty of power. The 2028 would double the weight of the truck!!! Well almost, that beast is the size of a coke can!!!
I would go with the 1717 merely because they are only like $50 if you can still get a few from the CC sale so you have back up motors, and they do turn out quite a bit of power. Of course if money is not your concern then go with one of the bigger Neu motors, but back ups will cost you a pretty penny. If you want some built in saftey for control I would go with one of the newer larger spec MGM series controllers. Just my 2cents.