IB3800 or IB4200 are great quality packs regardless of what company cycles and produces the pack with their name on it.

Purchasing a matched pack isn't necessarily the best purchase, they cost more and the advantage of being matched is gone after the first or second charge unless you are able to discharge the cells individually.

When charging the NiMah for the first time charge at .5 amps for the first 5 minutes then bump it up to about 5 amps (if the pack is outside the car) If the pack is inside the car charge at a lower rate to lessen chances of overheating of the battery.