Well i wud be using 2 x MRD-M300's as i have one already and wud buy another and the 2 subs.
Another question is , is it worth the extra cash for 2 subs over 1, bearing in mind i have one amp already.
In this case a single sub boxed is £134.99.
To have 2 subs its 2x £134.99 + £160 ish for the other amp = £294.99 extra for another sub.

Is having 2 the same significantly better than just 1 or am i best off to spend a bit more and get a single JL W3 V2??

Are you running them off two seperate amps or just one? If its two I always recomend two boxes just incase of any differences in amps. Two seperate is always safest two, if one blows then the other is still working in its correct enclosure. I too am running a pair of type R's with 1000W going to both. Ive found that sealed between 0.9 and 1cube each gives the best sound but im running 0.75 which is peakey but very punchy.:thumbs:

Right i plan to have 2 12" alpine type R subs and want to know which type of box is best.

Shud i get :-

2 seperate sealed boxs, one for each sub

OR

A dual sub box that both subs fit into??

Im thinking it wud be easier to manage 2 seperate boxs but dont know what difference (if any) the style of box will make to the sound??