Be careful on your muffler choice.
I just put a FlowMaster 50 Series Delta Technology Stainless on my 95 D90 and I absolutely hated it. It has a NICE growl when it's sitting still idling, but say going up a hill in 3rd gear in traffic with your foot just slightly on the gas is insane. And downshifting brings up another problem I had with it... it sputters, spits, and basically backfires. You might ask.... 'well Nick, maybe your engine isn't running that well ?...'
Nope. I run AMSOIL Synthetics throughout this beast and am religious with maintenance and now that I've put on the Stock muffler it's quiet again. I spoke to a couple of muffler shops BEFORE I put the FlowMaster 50 on and they said you won't get any horsepower increase, or a very small one at that.
I didn't want to go with a FlowMaster because of the sound and the guy at this particular muffler shop I went to said that with the 50 series, there are 3 'chevrons' which lessen the sound a bit but it was still too much for me.
On top of that the guy banged me $150 for the FlowMaster and you could buy it for $80 online. I was in a pinch and needed to rent a car that day to drive up to NJ from Florida so I said what the hell.
In any case, I drove it for that day, then called a Rover vendor and purchased one for $250. WELL WORTH THE MONEY, I can't tell you... even though I lost a good amount of my initial $150 FlowMaster price.
Some of the guys on here love the FlowMaster, but I hate it. The truck is loud enough without having to deal with that 'tin can' sound ...
If you do end up going with the FlowMaster you won't need a heat shield ... Just Ear Plugs!
Just my .01 Cent