It may be underpowered with the 150. You will notice that when you load up on fuel and passengers
I test rode an ‘89 Overnighter with a 175 Johnson OB. It had a hardtop which was really nice. I noticed there was marine growth which may have hampered its effort but it struggled to get up on plane even under full throttle and when it did finally plane it topped out at 34mph.
By comparison a test ride in my ‘87 Overnighter I ended up with with a clean hull and a 225, it planed instantly and topped out that day, 4 on board at 45mph.
I often wished I had that hardtop and wondered how much that marine growth held it back.
what I can say is the boat will always plane quicker and hold plane better with a larger engine.
That hull will plane in the mid 20’s and top out at about 34-35mph with a 150. With all that said in average sea conditions that hull with a 20’ boat isn’t going faster than 30 anyway.
I’d think you’d still like the boat with a 150 but when the time came you’d upgrade to a 200.