No we cant Install SSD ,Coz once you open your laptop to tweak the warranty will be void.
Asus K55VM and Dell Inspiron 15R Turbo both comes with i7 3rd generation but the difference is in processor's variant
Dell--3632QM-89th rank
Asus--3610QM-80th rank(Lower the rank is better CPU)
You can check the CPU comparison benchmarks from the below link.
PassMark Intel vs AMD CPU Benchmarks - High End
The Other important difference between the two lappies is GPU:
Dell has AMD Radeon HD 7730M, this is a class 2 mid range graphic card which has a performance of 27%.
Asus has NVIDIA GeForce GT 630M, this is also a class 2 mid range graphic card which has a performance of 25%.
So Dell has an Upper hand on GPU between the 2 lappies.
Comparison Link:Comparison of Laptop Graphics Cards - Notebookcheck.net Tech
All other features like sound,display,keyboard and battery of Dell are much better comapred to Asus.
Go for Dell!!!