Inset surrounds just cosmetic? and a couple other ?s

hey folks , getting ready to install my first pellet stove insert .

last weekend i bought/stole a vistaflame vf 100 insert and am prepping .

the stove came with a standard cheapo sheet metal surround . any reason i need to use it ? personally i can't see a reason , but thought i'd ask .

next question : how should the T be attatched to the stove outlet ?

i've got this flue kit coming http://www.rockfordchimneysupply.com/round-liner-kit.php and a dwyer magnahelic , some ht rtv and some 3m 600f tape .

since i'll need to be able to detatch it to service/repair the stove i was thinking a sheetmetal screw (or 2) and HT tape . remember this is an insert and not accessible w/o disconnecting from the T .

Thanx Woody

I believe the surround is only there to cover the opening left in the fireplace box after you install the stove. I suppose you could replace it with anything that is non-combustible.