My hyper 7PCR body shell doesnt have a hole at the back for the clip[X(].Also i bought a new high airflow filter and it seems a bit big to fit with the body shell on top.Is the original shell rubbish? Shall I buy a new one?

just drill the hole. The stock bodies are just fine. aftermarket bodies (like the proline ones) are a titch thicker (i beleive). But unlike MT bodies, i dont imagine buggy bodies get as beat up. The only reason to get an aftermarket is to do a custom paint job, or if you break yours somehow. Aftermarket bodies come uncut and undrilled so your still stuck drilling the hole...

lol drill your own hole.....

Should a drill or a reamer be used?

actually a super conductor laser pen is the best way to cut the holes....you can pick one up at lasers are us

either... and about the filter, ofna makes a wraparound filter neck..