To Buy or to DIY, here is my question

currently doing a set of DIY LS3/5a monitors and I am excited to hear how they will sound.

drivers are proven and matched.

had a shop CNC the MDF for the cabinets to my spec including bracing and grille frames.

crossovers were the biggest learning curve. online calculators are worthless.

download the program Xsim and experiment with it. with some online research I came up with a superb crossover design and know what parts to change if the voicing is too rich or too lean.

if they work out i sell my harbeths.  

Go DIY, my friend!  The satisfaction you experience will be tremendous! Every time you time your system on, you will smile. Most of the cost of "built" speakers is labor, cosmetics, and R&D. It's the drivers, the cabinet, and the crossovers that count. If you can get the cabinet pre-cut, that will help a lot (but shipping is expensive) and save you a lot of time. How the finished project looks is up to you. As long as no one in the house throws a fit, it doesn't have to look marvelous. GO FOR IT!

"@chorus I did build some Speakerlab cornerhorns once."

Well, building another set will be even easier then.  If you are not buying a DIY kit, paying for plans of a well proven and well tested design helps when the crossover and enclosure specs are included. Saves time to focus on a quality build for yourself.

How much to build mine?

What attracted you to the Proac speakers?

Have you seen https://meniscusaudio.com/product/er18mtm-ribbon-pair/

should sound similar to the Proac’s and what you’ll learn and the satisfaction derived could make up for the sound difference if any.

Also a fun read with some insight on what DIY entails.  

https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1637209185