BPS would be the last place I would let install a transducer. Once they drill the holes in the transom to mount it, it's a done deal, right or wrong.

Buy the plate to mount on the transom so they will screw into it and not your transom and that will fix that problem.

Your question is too vague. There are several different models of HB and Lowrance. You'd have to state which 2 you are comparing to in order to get a good answer. You can't go by someone stating that they had one brand and didn't like it and now they use another. Both of those brands have made big strides in improving their units in the last several years. Just because someone had brand A 5 years ago and think that brand B is better will mean nothing compared to todays units.

Either brand you pick is good. It is more of a Chevy vs Ford situation. Go play with them, get hands on and decide which one you like the best. Just tell the salesman that you are just looking and don't let them try and influence you. You don't know if they are getting a bonus for selling one over the other or even know what they are talking about. Either you choose will make you happy.

I'm wanting a 7 inch model with good down scan and side scan. Went to bass pro yesterday to talk to rep and he encouraged me on the Lowrance Elite-7 Ti, touch screen wifi, blue tooth model. I will go back next week with the boat and talk with a different rep and maybe get a more unbiased opinion. If I do purchase Lowrance, I will ask about mounting plate.
Thanks for the recs.

If you are still in the market, take a look at this weekend's offer on Lowrance at Bass Pro stores.
I really like the new HDS Gen-3 with the 3D bundle. The Elite-Ti w/Total Scan really works well at a great price point.

Im assuming you have already thought of this but just in case... take into consideration what trolling unit you want as it plays into your graphs "talking" to the trolling motor correctly.

Lowrance left us hanging on gen3 upgrade. Just bought gen 2 this year now there left behind i have chirp boxs chirp transducer and 12 7 and 9 on my boat fixing to make the swap to helixs 12 has better images and hummingbird seems to support there last year models