Berg 5 Speed Or Porsche 5 Speed?

[boygenius]

I was thinking about adding a fifth gear to my car and was wondering which route I should take. I already have a built 4-speed transmission. It has an aluminium side plate, close ratio 3rd gear with 3.88 r/p, welded gears, ect.......

I bought it for drag racing so 3rd gear is a little low, I think 1.48 but it has a stock 4th gear. So the question is whether to buy the berg 5-speed conversion kit or buy a 901 or 915 porsche transmission. I am always considering the cost of repairs if I break either one of the gear boxes. I already have the axles and cv joints for either of the transmissions. Any help would be appreciated.