wondering if anyone here knows how come r&d stage 1 is 2mph faster using a stock prop.. well so they claim 2mph

Assuming you are referring to the stage 1 kits for the RXP 215s I would have to ask where you received your information from....., After comparing information posted on both the Riva and R&D sites I have found that the R&D Stage 1 kits (base kits before any added options) for the RXP 215s are listed for $1,121.15, that's $386.65 more than the Riva stage 1 kits (before any added options), these retail for $734.50. The R&D kits come with the Solas 14/19 Concord Impeller, part #133-01419(not stock), advertised top speeds are 71.5-72 mph @ 8000 rpm. The Riva stage 1 kit comes with a Solas R-Series Concord Impeller, part #SRX-CD-14/19R (not stock) and has an advertised top speed of 72 mph @ 8100 rpm. I hope this helps to answer your questions, I can't see spending an additional $400.00 for no performance gains (you do the math)!!

i am sorry i am referring to the 255 rxp-x and they are about the same in price just r&d does not have the impeller i was just wondering how its as i said posted 2mph faster with out it?

Good question....., not real sure if the posted speeds are accurate. I would be asking if anyone has had experience with or heard of anyone running that set up to verify the speeds posted are accurate. Not trying to say anything bad about R&D, I know they make good stuff as well as Riva. I'm not real sure that the addition of R&D sponsons will give you an increase of 0.5 mph on top end????? Next time I'm on the river I'll get someone to drag me behind the ski to see if they even touch the water at high speed, hmmmm??? (just kiddin around).....

Actually, they claim 1 to 1.5mph faster than our Stage I Kit. But, they also claim to be running at 8,180rpm. While the X-boats will run above 8,100rpm our testing and inquiries to BRP have discovered that the stock rev limiter begins to kick in just before 8,100rpm. That is why we recomend running the craft at 8,000rpm with our Stage I Kit; which results in the slight speed difference. Running your craft below the range of when the rev limiter kicks in will ensure your craft runs strong and consistent.

so iam waiting for my nozzle an prop from riva it apears that i must remove my opas from my boat to fit this nozzle on 08rxtx mods to date riva grate catch can 4inch riva filter 69.9 gps fulltank is this true on the nozzle set up

No, you do not need to remove the OPAS system to run the nozzle...

thank you thank you its get alittle discro somtimes

3x your 69.9 makes me feel better. I was in choppy water but could only get to 70.0 but didnt seem like there was much left in her anyway. And you mentioning the fuel made me realize i had a full tank too. The nozel is an easy install.