I have a 93 170 TF single console, with a 115 Johnson, Everything works well. Merc is a great motor, make sure the lower unit is tight and hook up some muffs and make sure the water pump works good. A water test would be better. Also look at the controls or smooth operation.
For your question about a top, I have a top for mine, the person I bought it from used it when just cruisin around. The only place mine covers you is when your driving the boat,
Hope this helps you out a little.
Mark