Because the double roller has a life...most people who haven't replaced it after 20K are lucky...they aren't that strong, per say...and TONS of people have had them break...and it does nothing good for you. I busted a gear in like 3 places after only having mine for about 8k (I got SUPER lucky as the oil pump cover held the gear together)...got another one...ran it for 14k...no issues. Every local here has had nothing but bad luck from them...the chains stretch over the course of 15-20K easily...seen it.
Reptile is running a pretty nasty cam on 105's and a stock chain/dampner...pretty sure Trannyman95 is also running 130's on a stock chain/dampner...you just gotta let it idle higher, IMO that is the real kicker. Like I said...it's up to you...setting your idle around 800+ or whatever...and running 105's with a stock chain/dampner will be more than fine.
MAH00012.mp4 video by bluegtp03 - Photobucket