[Cockerill]

For equal capacity Lipo normally offer longer run times. A 3200 Lipo would probably offer the same or slightly longer run times than 4200 NiMH.

The 3200, 4900 and 5400 TrakPower packs fit straight into a B4/CR/B4 so I would assume they will fit into a RB5 as well. Looking at the dimension's on the TrakPower site the 3200 is lower than both the 4900/5400 so it may need some extra spacing.

The advantages of the Lipo are that they require very little maintenance and up keep compared to NiMH from my experience. This is great for a battery that will only be used for practice sessions. They can also be charged days/weeks before an event and still hold there charge.

It also means that your NiMH's will be kept in top condition for the races that count.