Usually the midpipe brand and the header brand have to be the same for proper fitment w/ long tubes. In other words- some welding/ cutting will be needed for correct fitment with the line up you have selected.
You could do your same setup w/ a MAC prochamber mid-pipe and it will work just fine.
mac LT's will only fit with mac mid pipes....unfortunately i know this because i found out the hard way by buying other midpipes and finding out during the process that they dont fit...
mac has a the flange area of their long tubes wider than the other brands so that they will fit around manual and automatic transmissions and to give you more room to work with.... stick with the mac LT's, they're a good header and the price is great... their midpipes are awesome as well