it will give you a little more lumens but save you money as well dont know if it will make a difference never grew with t8 but my t5s work great make sure its a 6400k
And yes, I would go with T5's..I used to have a 2ft, 4 bulb fixture in my old tent and it did great for veg..didn't get to flower the plant though, so I cant tell you about the the results with flowering. I know they sell a 2ft, 8 bulb fixture for like $180 at most Hydro stores, thats would I would get