The 18ss isn't a great engine! It's an awsome engine And if you bye a O.S 18 TZ you will need , Heavyduty Diffss.. Other wise within a few tanks you'l rip them out lol

Plus the 18ss is an O.S and it's powerfull enough i got TZ and normal O.S 18 And there just as powerfull as each other!..

But if it's what you want then that's completly up to you but the 18ss is a great engine =]