ok sorry to put ask a cycling tihng here but here goes :

just picke dup a set of new ksyrium elites for 500 bucks, now need the obvious cassette and rubber to go with them. is thre a huge difference besides cost in going for 105 vs ultegra? also, given that they say you should change chain and cassette togeather, is this going to play havoc with my training wheelset?

lastly, can any recomend a tyre to use? i dont want a full race tyre as the wheels will be used on group rides as well as racing, but somthing that rolls reasnobly well and remains tacky?

tks