I've had both stock BMW and Hepco&Becker on my R1100GSes. They're both good in their own ways but if I had to pick I'd recommend stock OEM guards.
They're lighter, doesn't bend that easily (they just don't have any "room" to be bent) as H&Bs do and if they do they don't damage header pipes and they're easy to bend back. Also BMW sells all the parts separately if you damage one of the sides - a big pro. I've done through a serious high speed crash and stock guards did amazing job - engine was one of the only "non-touched" parts of the bike.
Now I have H&B guards, they're nice, but I've done through a smaller crash - they're now bent, they dented one of my header pipes also, it could have been much worse, and now can't do valve adjustments (valve covers don't come off coz of bent guards) w/o taking the whole guards off anymore, and it's so bloody hard to bend them back because of their design. Currently I've just taken them off, I'll try to bend them again, if no success I rather ride w/o the guards or buy BMW stock engine guards again.
Touratech's are very similar to stock BMW 1100GS guards, but a bit easier on oil replacing and made apparently from a bit stiffer metal (on the contrary, I think the "softness" of the stock guard were they key that the engine was OK after the crash while I think stiff guards would have damaged the engine in contact). Removing sump guard with stock engine guards is easy if you learn the easy "trick" how to lift out the sumpguard out. I removed the 4 sump guard bolts and one of the inter-connecting arm bolts between the two sides of engine guards, lifted them a bit apard so they give enough space to slip the sump guard out on the bottom of the engine, and again in after you're done with oil.
Last edited by Margus; 11 Feb 2008 at 12:17.