Hi Stavros,
this is (or hopefully can be) a very interesting question.
This year, 2007, I have not competed in any events, however, I own three completed boats, with two "on the blocks". Complete boats are my Panther FSRO boat, the Miami OMRA boat and my play boat, the Mirage 2.
Out of all of them, I have had the most running hours out of my Prestwich Mirage 2FSRV, which I bought off ebay for 20 quid. It is a Mirage 2 with an SC61 engine, not that fast, the engine is not powerful, but it has done many, many hours this last year. I am using it to get my eye in for the coming season.
My other boats are much faster, but have not so far proven to be so much pound for pound fun.
I think it fair to say that the Mirage I own is one of these models that you do not really care about, but just keeps on going.
So Stavros, in anwser to your question, I would advise a secondhand boat where someone has it all set up and ready for you, or a race boat second hand. I am not 100% that you need a monster engine for your use..
Glenn