Take out the stock baffs and replace with the new. :?:
Unless you mean with the washer at the front or the rear then it doesn't really matter. At least to me, I put them in all 3 ways and heard nor felt any difference. 8)
Call BigCity and ask them what you need. I don't know about those pipes but all the TM I've seen are a direct swap. Pull out the stock, slide in the TM, no modification needed. 8) http://www.bigcitythunder.com
Product ID: D97-2010 Category: No Category
3" STRT THRU BAFFLE
Description: Louder than standard baffle. Sold Each
Price: $39.95 = $80.00 + S&H
Thunder Monster baffles $80.00 per pair + S&H
order by I.D." of straight thru baffle...
so far $160.00 plus shipping...this project is getting expensive..
it had better sound damn good......