Can anyone tell me the advantages/disadvantages of the two piece and single piece tail cones?

The advantage of the one piece jetpipe/ tailcone is that its twenty quid cheaper....$38...

I asked Wren the same questions..apparently the new machined single piece tailcone gives more consistent results from one engine to the next. There are more variables in manufacturing the 2 piece cone resulting in variances in performance. Consistency and repeatability are the name of the game here....although..if you get a really good 2 piece cone, it does produce slightly more thrust, but........

Thanks , I figured it had more to do with the fabrication than anything else.