My friend with an identical Sightseer '08 29R had Sumos installed in Sept. '16 by Hendersons's Line-Up and drove back from Oregon with nothing but praise. I had previously installed 1-3/4" Roadmaster sway bar in front (replaced stock) and added the Roadmaster 1-3/4" to rear with SuperSteer rear trac bar and Koni FSD's all around. I was REALLY happy with the upgrades, but after my friend added the same PLUS Sumos, I thought I'd do the same after a 7500 mile trip in Sept/Oct. Ends up that the Sumo's installed on my friends 18K chassis were intended for the 20-22K chassis (slightly taller, more load ability especially for rears). Chassis sits 1/2" taller (level), that's ok. Ride is firm, not too stiff. IMPORTANT: be sure you call Sumo for correct PN before purchasing! And if you install yourself, be EXTRA sure to check the inside of the frame rail before drilling ... especially driver's rear that carries a wiring loom. BTW, if you're comfortable with tools (and have the right ones), all these upgrades are not too difficult for DIYer. I saved enough to purchase and install 5-Star tune and full Banks. I have no issue with Henderson's .... they've done great work with alignment and other stuff over the years.
Wow, this is now a bitchen ride! I am a happy camper.
...keep a set of spare keys handy! '08 Sightseer 29R ('07 chassis 18K chassis); SCT Tune; Banks; RM sway bars; SS trak bar; Sumos; 480W GoPower; '10 CR-V toad