Re: Complete newbie...jumping right in.
I thought I'd add this about the power of the 3.0L.
Again, my boat is a 17'er, so keep that for perspective. This boat has plenty of power for me, I have not yet got into tubing. My normal lake is the Mark Twain lake in MO, off the top of my head I think its about 18K acres with and avg depth of 30' . Not very big by most standards, The water is not normally that rough. I share the water with other bowriders, pontoons, bass boats and a few house boats. I generally actually seem to have one of the faster boats on the water here, I have no trouble with power and I expect a 20' bowrider with a comparable engine would be just fine here.
Less often, I have been to Lake of the Ozarks. A 54K acre lake with an avg depth of 70'. The water is a little rougher here, but not terrible. The biggest difference is here you have much larger boats to share the water with, Speed boats, cruisers, sky is the limit here. This is where you will find the 130HP to be under-powered in my opinion. It isn't so much the water, If I am the only boat on the lake, I have no trouble. But the wake of larger 150HP+, 25'+ boats is a handful. It is more work than pleasure. I consider my boat to be of absolute minimal size for this lake.
I guess my point, is too not only consider the size of your lake, but the boats you will share the water with. If you just want to cruise around in calmer water with comparable boats, you'll be fine. If you are going to tote around 6 adults, tubing, with boats that are larger and more powerful than yours. You will not be happy with that 3.0L
If you do some research, you will find the 3.0L and Merc Alpha one stern have solid reputations. Like I said I get phenom gas milage and the power is more than adequate for my normal lake conditions, but I would consider the other boats you would share water with, this is where I find power comes in handy, more so than just the size of the lake. (of course, larger lake generally = larger boats)