IMO: T56 6sp
Requires a turbo bolt pattern block or a aftermarket bell housing for trimatic blocks. There are multiple sites selling them on eBay, just a little massaging of the tunnel required, plenty of posts on this site. Speedo will require a "black box" to convert electric sender input to mechanical output. Clutch only requires 6 cylinder pedalbox with an under dash master cylinder & internal concentric slave cylinder.
T5 wont take a beating if you want to flog it continuously with a healthy 355, however still not a cheap option as you will need to find a V8 manual pedalbox $500-ish (hard to find these days), Holden V8 T5 $2k-3k, again aftermarket bell housing if you have a trimatic block!