Thoughts... RC4wd.com's Heavy Duty R2 transmission in E-maxx??

Actually its a t-maxx. My old s-maxx is getting tired of being nitro and i want to covert it to brushless. I've considered either just putting a new e-maxx transmission in it or using rc4wd's HD R2 trans. They said it can take that much power. The gear ratio has me confused. Their site says it can use a 10:1 to a 30:1 ratio. Whats the trans ratio for the new e-maxx. Nevertheless, if i did use this trans i would make my own moutings so i know that. What are your thoughts on this idea?? Also, can someone tell me if the all metal gear set for e-maxx trans on rc4wd's site is for the old or new e-maxx?? If they were for the new one, i would consider using them to beef up an e-maxx trans instead.

heres the links

hd r2 trans
http://rc4wdstore.com/product_info.p...roducts_id=747

e-maxx gears
http://rc4wdstore.com/product_info.p...roducts_id=384