An upward angled stem and larger cog on rear cassette is the usual mod for more long distance comfort.These wont cost the earth and the original;s could be put back on in 15 minutes.
This ^^
Essentially, a sportive bike has a taller head tube, meaning the bars are higher, in relation to the saddle (there are some frame geometry differences beyond this such as wheelbase etc but forget that for a second). To get the bars higher vs the seat on a race bike, flip the stem (take it off, turn it upside down and put it back on - they are designed to allow this, hence the graphics are usually right either way up, and the face plate is reversible). If it is not high enough, buy one with a more dramatic angle (won't take much) and flip it. Won't dost much and the stems with the required lengths and angles are readily available. A cassette with a larger cog is also fairly cheap and readily available if you need easier gearing, not necessarily the case.
To lower the front end on a sportive bike to the degree it puts you in a full on race position you would be looking for a stem with a silly angle, probably something not as readily available, expensive or heavy and made mainly for track use.
As for the geometry differences I alluded to above, these mainly affect handling with a minor effect on "comfort". 1st, thinking about handling, a road race bike will be more twitchy and more responsive when thrown about, i.e. when you really dive into a bend or try to get round someone with a rapid movement, a sportive bike in theory would be less responsive and more happy to make less sudden movements and to go in a straight line. "Comfort" wise, the wheelbase and geometry of the road race bike vs the sportive bike results in minimal difference comfort wise (i.e. you gain next to nothing going for a sportive frame), but substantial handling wise (you lose a lot of the potentially handy handling characteristics of a race bike when going with a sportive frame).
Basically, if all you will ever do is pootle around on sportives, then a sportive bike may be the better choice, I am not trying to put you off that choice. BUT if you see yourself racing some point down the line, you may be better with a race bike, because, odd as it may sound, they are more versatile.