ABU REEL INFO
ABU 6500 C series Bearings
C3 = two ball bearings in the spool, one anti-reverse
C4 = two ball bearings in the spool, one anti-reverse, one ball bearing in the level wind
C5 = two ball bearings in the spool, one anti-reverse, two ball bearings in the levelwind
7000C3/7500C3 reels have two ball bearings at the ends of the spool axle plus a third ball bearing around the crank shaft
A C3 has a lower gear ratio than the C4 but the difference in actual use is around 4" of line per handle turn.
A new reel will be made in Asia, seem stiff to use and will require some time to 'run in' before it performs perfectly.
A Swedish made 2nd hand reel is altogether a better option, IF you can find one.
Replacement ABU parts are readily available as are service engineers and upgraders.
The C4 holds many of the UK distance casting records.
Hope this helps.
PS I use a Shimano Calcutta D but my back-up is a C3.
I've got a Swedish 5601 c4 jerkbait edition that I let my mates use when they come piking with me and it's ok and will do the job but compared to shimano multipliers they are a bit agricultural and don't feel as solid . I got it in a deal along side a none Swedish model (can't remember which one but it was silver but not c3) and the none Swedish lasted about half a dozen trips at most before breaking . Same as the above poster I use shimano multis and I've never had a single problem with any of them . If your not looking to spend a lot have a look at the corvalus and Cardiff models they are bombproof . The Calcutta d is a quality reel but unfortunately the 401 is discontinued (at least over here) and only available in the 201 size now , which might not have the line capacity you need . If you've set your heart on an Abu and can't source a Swedish one it will be worth joining some pike/lure forums and putting a wanted ad on because they come up for sale on there regular