I think that if you buy new irons with a genuine expectation that they will improve your scores, you are going to be disappointed.
Unless your older clubs are X stiff blades from the 1970s you basically buy new irons because you want new irons.
I really liked this plastic tee this past summer....I think I used it for 2 months....I think it fell out of my pocket...ugh....I might still be playing with it.
I've also not bought a golf ball in maybe 30 years....I find so many...have a lot new golf balls from promos, corporate swag, etc.
Before I spent $1150 on new irons I would want to test my current irons against the new irons on the same monitor, i.e., bring you current set in and hit them as well. I'm not sure I trust the monitors in all these stores, I may be wrong but I don't think I have ever achieved the distances these monitors predicted once I got on the course. And also as stated above the manufactures have changed the lofts over the years.
You are hitting the Speedzone irons really far because the irons are so JACKED UP.....the 7 iron is 27.5*...that's whacked...my 7 iron is 34* and 6 iron 29.5*.
Though your current irons are also JACKED UP too....7 iron at 30".
Just because dispersion is better on the monitor....it might not translate out on the course.
Based on what you have wrote...I wouldn't buy the irons...you don't seemed convinced you need new irons to enjoy the game more...new irons won't magically lower your scores.
Cobra clubs don't hold their value well if you decide to sell.
Only you know whether you want to spend the money.