Performance (draft+) of different length pipe

Ok, this question isn't quite as obvious as the thread title makes it sound.

I'm going to be installing my insert soon and will be using Duravent Rigid Oval out of necessity.

I am able to get shorter pieces of liner more cheaply per foot than longer pieces (odd, I know). So my question is, would there be any performance or other drawbacks to say, using 8 2-foot pieces of liner rather than 4 4-foot pieces?

I suppose the extra screws would have a minor draft impact... but is there anything else that would be a drawback that I'm not thinking of?

Thanks for the replies guys. I ended up finding some 4' pieces that are better priced - still a bit more than the two 2' pieces but close enough that I think I'll just go with the 4. And thanks for reminding me about the length lost per splice double-d, that's going to be important because I want maximal height above the top of my chimney (at least 1 4' piece there). Chimney is only 13' so I'm going to try and get as close to 17' feet as possible.

I wouldn't have to plan it so precisely but duraliner says not to have any seams present above the top collar, so I'm going to have to get the top seam as close to it as I can for max length.