Jorge, keep in mind most of those motors can be converted to a 25" shaft with a simple 5" extension kit, whenever you decide to raise the transom. If you're firm about getting a bigger motor I'd seriously consider raising the transom now as others suggested.
Here is a link to a well known aftermarket shaft extension manufacturer.
www.baymfg.com
Go to nada.com and check the weights of the motors you're considering. That late 80s merc 150 is about 375 lbs,
every thing else is likely heavier. The lighter, the better.
If your transom has not been refurbished I would wait on the high powered motor idea... 1200 dollar 115 - 130 will be will be much easier on the transom and perform just fine...
Good luck.