To be honest, I think improved rounds look COOL. Along with the fact that the 338 Lapua brass is top notch, and top end velocity should be more with the Lapua improved. It gains a lot of capacity. I'll put up a pic with a fireformed round.
I wouldn't be surprised if you would get more than that. My cousin is getting 2981fps average with a 11fps ES with 92.2grns of H1000. Retumbo was much slower by about 50fps. He is shooting a regular 338 Lapua with 300SMK. Its coming out of a 32" Douglas heavy barrel.