I would get the VRSF and install them yourself.
I previously had a 135i. I have zero mechanical skills. I installed a set of AR pipes in a parking lot on Rhino ramps. It was not so bad. I don't think it would have been much easier on a lift. The lift would not give you any more space in the tight areas and you would have to have your hands above your head which would get tiring.
Over the couple of years I had the car I uninstalled and re-installed them a few times. I would have spent a lot if I had to pay someone for all that. After the first install I got a set of the flex head gear wrenches. These will save you a lot of time! The hard bolts are the ones that secure the DP to the back exhaust and the ones that tighten the clamp that holds the front part of the pipe to the turbo. I think they are either 12mm or 13mm (check the DIY guides). Trust me, get the flex head gear wrench in this size (I got mine at Lowes) and it will save you a few hours.
When i sold my 135i, i sold off my AR pipes. I recently got a 335i. I have always thought the ARs are the best DPs on the market. That said, I could not resist the incredible price of the VRSFs. I just got a set of VRSFs delivered today and to my delight they are basically the same as the AR's
I haven't installed them yet, but i think I will be very happy with my choice.