Tires: v rated or h rated, maximum speed capability, pot holes

Question
Hello John..I read your profile, very impressive, congrats!! I have a dilema and need an unbiased answer. I have a 2007 ME/BE E350 sport. I live in NY and constantly dealing w/ pot-holes. I have conti pro contacts now (oem). size is 245/40/18/v(front) & 265/35/18/v (rear). The tire shop reccomended I put same tire but "H" rated, saying it will last longer, cheaper, and better. How do you feel about that because I have had other BMW's w/ these tires and its getting a bit expensive now constantly changing tires. BTW, I got the car in middle of March and now has 8000 miles and I already need at least 2 new ones. Thank you "very much" for your feedback.

Answer
Thank you.  Well first thing first.  I would recommend that you fine a different tire shop and never go back to that shop again.  Failure to follow correct tire safety can result in injury or death.  We do not want any of those.  
Speed rating is for:
-Safe performance of tires at standardized speeds.
-The speed rating of a tire indicates the speed category at which the tire can carry a load under specifies service conditions.

What happens when you lower your speed rating is:
-Effects handling.
-Lost of maximum speed.
-Speed odometer not working correct and giving false speeds.
-May effect your car Differentials.

When you lower the speed rating lower then the OEM:
-The handling of the vehicle may be different and the maximum speed capability is limited to the lowest speed
rating.

Here is a tip for speed rated tires, which will be hard for you since you run two different tires.
When replacing two tires, and they are speed rated, they must go on the back for control.  If not, you will spin out of control.  ( this apply's only to wheels of 4 tires of the same size ).

I have seen many people get raid of there cars after they find out the cost per tire and how often they have to replace them.  When I buy a car, the first thing I look at is the tire.  ( its a hidden cost ).

So to answer the question, no.  Do not lower the speed rating ever.   You can always go up in speed rating, but never down.  For best results, stay with oem size, speed and load.

Hope this helps.
Good luck,
John