I'm about to find out first hand if 1.7 RRs will fit under stock valve covers. I've heard you have to "massage" the baffle in the underside of the covers. In the next couple weeks I'll be installed Proform 1.7 RRs on my car. I know, I know - Proforms!?!?!? Well, I had already won a new set on ebay before I read about some of the issues. I'll give them a shot and if they break and take the stock heads with them then meh, it's an excuse to upgrade