Hello Littlened
I had a lazer rtr with the standard radio gear which i upgraded to a 4.5 brushless setup. I had EXACTLY the same problems as you have described.
To make things better with the 27mhz am system i put the recielved up on the bar that goes front to back in the middle. I positioned it near the back on its side so the shell could still fit.
I also fitted a Spectrum power cap, one of these.
http://www.dms-racing.com/fruzat/qax...SQL/search.asp
(Hope DMS don't mind the link)
You need a spare slot in your reciever to plug it in
Make sure you have good quality new batteries in the Handset
This all made a big enough difference for me to get it round the local track without issue.
Long term i purchased an acoms 2.4ghz wheel set and have never had a problem since.
Hope this helps