Mods...everybody makes 'em, some much more than others.  Everybody likes to talk about 'em.  We experimental aviators are a tinkering bunch.  Each modification is a great idea in the mind of its inventor...and a terrible one according to someone else.  Each increases aircraft weight, which is bad; each adds some design risk.  Since I'm building the plane of my dreams here, it must suit ME...but I don't intend to spend the next few years squaring a circular wheel, so I'll mod what I feel I must, and try to leave well enough alone.
    I can't recommend ANY of these mods, since I haven't proved them in flight.  I think they'll work for me; what works for you is another kettle of fish.
    That said, I'll note that there's almost no such thing as a "stock" Long-EZ.  There are the changes and updates covered in Canard Pusher, which I'm not going to mention, and a number of other mods which over the years have become almost standard.  Then, there are others that are just nice to have....
    Mods I'm making:

    Electric Speed Brake   (note my high-tech 12-volt battery)
    Wortmann Symmetrical Gear Leg Fairings
    Front-Mounted Brake Cylinders -- basically per Deb Iwatate , but with a custom widget to allow E-Z rudder pedal adjustment.
    Rear Canopy Arch instead of arrow stock.  The backseater will love me for it.
    Ram air cooling for the rear seat -- a NACA duct feeds a fisheye vent.  Also intended to win points with the backseater.
    Canard hole covers -- I want cooling air on demand, but not ALL the time.  These keep the hole covered at any elevator position, and weigh and cost about nothing.
    Heated pitot tube.
    Deb Iwatate 's canopy latch.  I modified the mod by skipping the access door.  A key set into the fuselage side pulls on the canopy release and gets it open enough that motivated fingers do the rest.  Locking is accomplished by lowering the canopy to 1/4" above the rails, then finishing with an AUTHORITATIVE push.
    Landing light is a 75W narrow-beam track light, not the per-plans glass monstrosity.
    Increased-span ailerons -- my ailerons extend outward 20" more than plans, necessitating a fourth hinge position.  To prevent wing torsion from negating the benefit, a wing pin holds the wing leading edge in place against the strake.  The wing pin complicates wing bolt installation considerably; it's probably not worth it.
    O-320D2B (160 HP) Engine.
    Big rudders
    Flush rudder bellhorns
    "Unkinked" strakes -- straight line along the leading edge; fuel and baggage slightly further forward, Cp doesn't move much.  Done largely because it means I could use strakes direct from Aerocad, instead of doing it myself.
    Downdraft cooling, with over-the-shoulder intakes and a smaller NACA on the bottom to feed the carb air intake and cool the mags.
    Aileron end plates, inboard and outboard .  Should prevent spanwise flow and keep control surface effectiveness at low speeds.  Cribbed shamelessly from Klaus Savier , of course

    Then there are things I just don't have the time for, and/or I bought a project where these steps had already been done.
    Mods I am NOT making:

    Roncz canard -- I inherited a built per-plans GU canard, and I plan to run with it.  If it changes pitch trim in the rain, badly, then I'll have a future project once I'm flying, but not before.
    Removing the lower winglets -- One significant aerodynamic mod should be enough.  Besides, removing the winglets don't do anything detectable for speed, but might have adverse effects on stall/spin characteristics.  I'll keep those lower winglets on!
    Electric nose lift.  They seem great, but I can live without 'em, and I have to stop modding and GET FLYING sometime.  Perhaps I will retrofit this later.
    Electronic ignition.   As for the nose lift.  I want 'em, and will probably retrofit them as my magnetos crap out.
    Wider fuselage, panel, and canopy -- Everybody should probably do this, but it's too late for me.
    Retractable main gear.  Tempting, but no.  Not at this time.
    Longer nose -- I inherited a per-plans nose, though it had been built with enough "roundness" that it's not as downright ugly as most per-plans noses.  I'm going to press on with it, as a per-plans nose can be made to work with an O-320 in the back; especially as I'll have a full IFR panel and front-mounted brake cylinders (read:  forward ballast).  Also I weigh 210 lbs or so, so I'm forward ballast in my own right.
    Still, you guys with Ronnenberg noses are COOL.  Sigh.