Don't get a 2871. This has been discussed here many times, the 2867 spools faster, has better transient response, and makes very close to the same peak power on the GTE.
I tried searching and saw some old post with discussions on it. but i also saw one guy putting down 400hp on a 2871 snd he said he was getting spool by 3000 rpm, but was on a 3sge so i think that might of been from the higher compression that helped. I tried looking up the 2867 you suggested and the only one i see come up is the gtx model, is that the one you talking about?