I am about to make the leap and buy a 6-speed Bromptom M type. I will definitely need to add new grips to add 1 or more hand positions. I'm considering the Ergon's (https://www.ergon-bike.com/us/en/home#) which I've seen mentioned on other posts. My questions are:
1) Is it easy to add a GP4 or a GP5?
2) Do either of these grips affect the fold?
3) Can the bike be packed in the travel case with these grips?
4) Should I be considering other grips?

Thanks!

Re (2) GP 5 you have to Loosen, the Bolts and rotate the Grip,
on the bars to fold it or it wont reach the catch pin, do that ant they are out of the way.

GP 3 you Dont. I've got those on a 2 year old M3L Bike.

never tried the 4.. fit ? Its easy on the new bikes ,7/8" bars. ,
Had a older Mk2, its bar is 15/16 so they didnt fit.

Considering getting the one without the Bar end at all , a bit of the reach around issue,

but I can catch the tip of the brake lever from the Bar end with my fingers ,
(the brake levers are different now, better, many say, )

But its not a powerful grip. a slow down, not a panic stop.

dont own a case. so IDK 1 bolt removes each if there is a packing interference.

Even the Ergons without bar ends offer 2 handpositions (you can rest the heels of your hands at 90° to the bar, on the wide end of the grip).

Another manufacturer of that style of grip worth looking at is Herrmans (Finland).

Ergon's Phorm is a simpler version, But there is no shorter double gripshift version..
so a little DIY is required.

I added a wrap of remnant, Bartape to the grip-shift set, as they could ideally be 2cm wider,
but that was simple to do.

Space on the M bar, falling a bit longer than the short, but shorter than the long.. so to say..

Even the smaller ones line GP2 or GP3 will give you an additional hand position.

I am using GP3 on my S and am very happy with it. I prefer to have the weight on the grip itself rather on the barend alone so don't need a longer barend. Also using the Ergon ls100 for extra peace of mind.

I have the GP3...they are nice hardware but I cannot get comfortable on them no matter how I have tweaked. I am fan of the Cane Creek Ergon style. Watch out for the cheap knock offs of this style as they have a plastic core not aluminium like the originals.

https://www.amazon.com/Cane-Creek-Erg...ef=cm_cmu_pg_t