Glen,
I am in favour of the Transgo shift kit. As you know I have this tranny job underway and as part of the planning have begun gathering parts as follows:
Techtran Guide book for the 45RFE's and 545RFE's (112 pages),
filter set & gasket kit (neoprene pan gasket),
2 x pan drain plug / bulkhead sets (we've discussed that elsewhere on forum) and
HD tranny cooler (Hayden) + frt for a quite reasonable price as a package.
Am purchasing from Cascade Transmissions. They DO answer e-mails. Have lots more items for our transmissions that are not yet listed on their site including speed sensors, solenoid blocks and tranducers for our transmissions and many others including Allisons, GM etc. Freight, too, is reasonable.
Their sites are:
http://www.electricaladvantage.net
http://www.cascadetransmissionparts.com
The comment that Robert made (Cascade owner) made is that the Sonnax piggy back PT # 44957-LB2) is they don't sell it as the Transgo kits resolves most issues related to the trannies with shift quality etc. As I have no issues and just want a more responsive shift pattern to load situations etc. I'll install the Transgo when the valve body is accessable when the new TC goes in and give her a chance to learn the shift pressures before deciding on the Sonnax. All this for more durability. Two other things to add and I'll be happy with the tranny. (I think).
Cheers