[WTA] about 15r se possible configuration, SSD config

Hi all sifu, I have been planning to get a new laptop as a workstation and a replacement to my aging desktop at home. Currently I had narrow down to Dell Inspiron 15r se(FHD + msata combination) and has been thinking regarding the possible SSD configuration.

1. Replacing msata of 32gb to bigger size such as 120/180 as a primary drive.

After some research, it seems pretty possible to replace the msata ssd to a bigger size with a sata capable of 6 Gb/s. However, the msata seems not pretty feasible if I change my mind to replace my msata card else where.

2. Slot in 180/240 GB 2.5" SSDas primary drive + swap ODD for HDD caddy combination.

It seems pretty good as new Intel 335 series 240gb seems to be in a pretty decent price for the storage size. However, it seems that if I plug in the SSD, it only capable to run in 3 Gb/s as I did some search online(still not pretty sure of it).

If this was possible, was thinking if I'm able to raid the msata 32gb available with the 1TB drive located in HDD caddy to slightly improve caching on retrieving files? However, I think ACHI mode were needed to recognize the primary SSD during the installation. This going to be my first SSD so I'm not really sure if anything I missed.

Mainly, I may be dual booting windows and Ubuntu build and thinking which type of configuration would be better. Any advice or pointers on my proposed configuration are welcome.