a coupla reasons i guess.....
easier to plumb the turbo oil drain for one
and general plumbing of boost tubes+intake is easier IMO
i would like to set it (manifold)back like 3/4 of an inch or so for better intake clearance
longer studs and spacers that resemble 3/4 inch thick "gaskets" will do the trick....
yea you get more intake clearance the other way for using a "gasser" style long runner intake,but exhaust routing looks like a headache
(im picturing an older callaway gasser look to an "under" turbo setup...)
heres a few pics

before,sort of,1 patch in there:

its funny,the welds look worse in the pics
:cry: hey i said i could weld,,,,you didnt ask if i was GOOD at it :lol:

after,and im welding seams while im at it too: