Type RA gear ratio and taller 5th
 

Hi people, my box has recently blown on my 94 Type RA.

5th is missing almost every tooth, damn.
It's proving really hard to find a 5th the same ratio as I have already.
I have the chance to add a taller 5th instead.
I know allot of RA owners do this but I dont want it to drop so much going from 4th to 5th.
Whats the difference like?
I dont really do allot of motorway driving but at 80MPH it's around 4500rpm, so I do get a little concerned.
I'm not too excited about top end in a car, never have been.
It's always been about 0-60/80 for me.

I'm really after your thoughts, before I decide.

Thanks in advance