I would be looking at two factors:
`1) Cost of engine repair/rebuild and reputation of the shop who would be doing the work
Although it sounds like you still really love your boat, and was considering new carpet and seats, I agree with Tim above that putting a brand new engine on a near twenty year old boat is not a wise move, nor is a used engine. If the cost of a rebuild is not off the charts, and the shop does great work with some warranty, then fix it. You could then still run it, and, if the new boat bug crops up later, you could at least sell it in good running condition.
2) your personal financial circumstances and desire for a new rig.
Like you, my go fast days with 20 footers are behind me, so, when I decided to get another boat eight years ago, I downsized from a Cougar to a P2 (and then to my present Classic). I have no regrets at all being in the 19 footers. Financially, it was a much easier move to downsize into a new 19 footer than to consider another 20 at that time. Of course, how and where you fish is a consideration for boat size.
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